The basic steps for attaching a file

To attach a document to an email, open your email program or website, start a new message, and look for a button or icon that represents a paperclip or the word "Attach". Click it, then navigate to the file on your computer that you want to send. Select the file and confirm — it will appear as an attachment in your email before you hit send.

The exact location of the attach button varies depending on whether you use Gmail, Outlook, Apple Mail, or another email service. But the concept is the same across all of them: you're telling your email program to bundle a copy of a file along with your message text.

One important thing to know: attaching a file sends a copy to the recipient. The original file stays on your computer. If you later change that file, the recipient still has the version you sent — they don't automatically get the updated one.

Key Takeaways

  • The attach button is usually a paperclip icon or labeled "Attach" and sits near the send button in your email program.
  • File size limits vary by email service — Gmail allows up to 25 MB per message, while Outlook allows 20 MB, and some services allow less.
  • Common file types like PDF, Word documents, and images attach without problems, but some file types may be blocked by your email service for security reasons.
  • If a file is too large to attach, you can use cloud storage like Google Drive or Dropbox to share a link instead of sending the file itself.

Where to find the attach button in Gmail

In Gmail on a computer, open a new email and look at the bottom left of the compose window. You'll see a paperclip icon — that's the attach button. Click it and a file browser will open, letting you navigate to any folder on your computer and select the file you want to send.

On Gmail's mobile app, tap the paperclip icon at the bottom of the compose screen. You can then choose to attach a file from your phone's storage, or take a photo or video directly from your camera to attach.

After you select a file, Gmail shows you a preview of what's attached. You can add more files by clicking the paperclip again, or remove an attachment by clicking the X next to its name.

Where to find the attach button in Outlook

In Outlook on a computer, start a new email and look for the "Attach" button in the ribbon at the top of the compose window. Click it and choose "Browse This Computer" to find a file on your device. Outlook will then show the file as an attachment in your message.

In Outlook's web version (Outlook.com), click the paperclip icon at the bottom of the compose area. You can attach files from your computer or from your OneDrive cloud storage — if you choose OneDrive, Outlook will insert a link to the file rather than attaching the file itself, which saves space.

Outlook also lets you attach files by dragging them directly into the compose window on a computer. Simply drag a file from your file explorer into the email and it will attach automatically.

File size limits and what happens when a file is too large

Gmail allows attachments up to 25 MB per message. Outlook.com allows up to 20 MB. Other email services have different limits — Yahoo Mail allows 25 MB, while some corporate email systems allow less. If you try to attach a file larger than your email service allows, the email program will warn you before you send.

When a file is too large, you have two main options. The first is to use cloud storage: upload the file to Google Drive, Dropbox, OneDrive, or a similar service, then share a link to that file in your email instead of attaching the file itself. The recipient clicks the link and can view or download the file from there. This also means they always see the most recent version if you update it.

The second option is to compress the file, which makes it smaller. On a Windows computer, right-click the file, select "Send to", then "Compressed (zipped) folder". On a Mac, right-click the file and select "Compress". The compressed version is usually 30 to 50 percent smaller, though this doesn't work well for files that are already compressed, like photos or videos.

File types that may be blocked or cause problems

Most common file types — PDF, Word documents (.docx), Excel spreadsheets (.xlsx), images (.jpg, .png), and text files (.txt) — attach and send without any issues. But some file types are blocked by email services for security reasons.

Executable files (programs that run code, like .exe or .app files) are almost always blocked. Email services also often block files like .zip archives, .bat files, and other types that could potentially contain malware. If you try to attach a blocked file type, your email program will show an error message and won't let you send the message.

If you need to send a file type that's blocked, compress it into a .zip file — sometimes this bypasses the block, though not always. Another option is to upload it to cloud storage and share a link instead. If the recipient needs to run a program, they should download it directly from the official website rather than through email.

Attaching files from cloud storage instead of your computer

Most email services now let you attach files directly from cloud storage without downloading them to your computer first. In Gmail, click the paperclip icon and you'll see options to attach from Google Drive, as well as other services. In Outlook, you can attach from OneDrive the same way.

When you attach a file from cloud storage, the email service usually inserts a link to the file rather than copying the entire file into the email. This saves space and means the recipient always sees the current version — if you update the file in cloud storage, they see the update without you having to resend the email.

The downside is that the recipient needs access to view the file. If you share a Google Drive file, they need a Google account. If you share from OneDrive, they may need a Microsoft account. For this reason, attaching the file directly to the email is sometimes simpler if the recipient doesn't use the same cloud service you do.

Confirming an attachment before you send

Before you click send, take a moment to verify that the correct file is attached. Look at the attachment preview in your email — it should show the file name and, for some file types, a small preview of the contents. Make sure it's the right file and the right version.

This is especially important if you're attaching a document you've edited multiple times. It's easy to accidentally attach an old version or the wrong file entirely. Most email programs show the file name clearly, so reading it takes just a second and can prevent sending the wrong thing.

If you realize you attached the wrong file after you've already sent the email, you can't unsend it in most email services (though Gmail and Outlook do have an "undo send" feature that works for a few seconds after you hit send). The best practice is to check before sending, not after.

Frequently Asked Questions

Can I attach multiple files at once?

Yes. Click the attach button multiple times and select a different file each time, or select multiple files at once in the file browser by holding Ctrl (on Windows) or Command (on Mac) while clicking each file you want. All of them will attach to the same email.

What if the recipient says they didn't receive the attachment?

First, check that the file actually attached — look at the attachment preview before you sent it. If it did attach, the file may have been blocked by the recipient's email service or spam filter. Try sending it again, or use cloud storage and share a link instead. If the file is very large, it may have been caught by their email system's size limits.

Can I attach a folder instead of individual files?

Most email services don't allow you to attach a folder directly. Instead, compress the folder into a .zip file (right-click and select "Compress" on Mac, or "Send to" then "Compressed folder" on Windows), then attach the .zip file. The recipient can unzip it on their end to access all the files inside.

Is it safe to open attachments from people I don't know?

Be cautious. Attachments are a common way malware spreads. Don't open attachments from unknown senders, especially executable files or Office documents. If you're unsure whether an email is legitimate, contact the sender through another method (like a phone call) to confirm they actually sent it before opening anything.

Can I attach a file that's currently open in another program?

Yes, you can attach a file even if it's open elsewhere. However, if you're actively editing the file in another program, save your changes first so the recipient gets the most recent version. Some programs may also lock the file while it's open, which could cause issues when attaching — saving and closing it first is the safest approach.