The fastest way to attach a file in Outlook

To attach a file in Outlook, open a new email or reply, then click the Attach button in the toolbar — it looks like a paperclip. A file browser window opens where you navigate to the file you want, select it, and click Open. The file name then appears in the Attachments area below the message body.

The exact location of the Attach button depends on which version of Outlook you use. In Outlook on the web (the browser version), it sits in the toolbar above the message box. In Outlook desktop for Windows, it's in the ribbon at the top. On Mac, it's in the message toolbar. Once you click it, the process is the same across all versions.

You can attach multiple files at once by holding Ctrl (Windows) or Command (Mac) while clicking each file in the browser window, then clicking Open once. All selected files attach together.

Key Takeaways

  • Click the paperclip icon in the toolbar, browse to your file, and click Open to attach it to your message.
  • You can attach multiple files at once by selecting them together in the file browser before clicking Open.
  • Outlook on the web, desktop Windows, and Mac all have the Attach button in different places but work the same way once you click it.
  • File size limits vary by your email provider — Outlook.com allows up to 20 MB per message, while some organizations set lower limits.
  • If your file is too large, you can use OneDrive or SharePoint to share it instead of attaching it directly.

Where to find the Attach button in each version

Outlook on the web (mail.outlook.com or your organization's webmail): Open a new message or reply. In the toolbar above the message box, you'll see a paperclip icon. Click it to open the file browser.

Outlook desktop for Windows: Open a new message or reply. In the ribbon at the top of the message window, click the Attach File button. It's usually in the Insert tab, shown as a paperclip icon.

Outlook for Mac: Open a new message or reply. In the message toolbar, look for the paperclip icon and click it. If you don't see a toolbar, go to the Message menu at the top and select Attach File.

Outlook mobile app (iPhone or Android): Open a new message or reply. Tap the paperclip or plus icon at the bottom of the compose screen, then select Attach File or Add Attachment from the menu that appears.

File size limits and what to do if your file is too large

Outlook.com and Microsoft 365 accounts allow attachments up to 20 MB per message. If your file is larger, Outlook will block it and show an error message. Some organizations that use Outlook through their own email servers set lower limits — check with your IT department if you're unsure what your limit is.

If your file exceeds the limit, use OneDrive instead. Click the Attach button, then select Cloud Attachments or Browse Cloud Locations (the exact wording varies by version). Upload your file to OneDrive, then insert a link to it in your message. The recipient can download it from there without hitting the attachment size limit.

Another option is SharePoint if your organization uses it. The process is similar — you upload the file to a shared folder and send a link instead of the file itself. This also makes it easier for multiple people to work on the same document without creating conflicting versions.

Attaching files from cloud storage like OneDrive or Google Drive

You can attach files directly from OneDrive without downloading them first. In Outlook on the web, click Attach, then select Browse Cloud Locations. Sign in to your OneDrive account, navigate to the file, and click Attach. The file is inserted as a link, not a copy, so the recipient always sees the latest version.

In Outlook desktop for Windows, click Attach File, then look for Browse Web Locations or Recent Cloud Files depending on your version. This works the same way — you're creating a link rather than copying the file into the message.

Google Drive files can be attached similarly in Outlook on the web. Click Attach, then Browse Cloud Locations, and select Google Drive if it's available in your account. Desktop versions of Outlook have more limited cloud integration, so downloading the file first may be simpler if you're using Outlook for Windows or Mac.

What happens after you attach a file

Once you attach a file, its name appears in the Attachments section below the message body. You can see the file size next to the name. If you need to remove it, click the X next to the file name or right-click it and select Remove.

Before you send, check that the right file is attached — it's easy to attach the wrong version by mistake. The recipient will see the attachment in their inbox and can download it by clicking on it or right-clicking and selecting Save.

If you're sending to someone outside your organization, keep in mind that some email systems scan attachments for viruses. This can add a few seconds to delivery time, but it's automatic and you don't need to do anything.

Drag-and-drop attachment in Outlook on the web

In Outlook on the web, you can drag a file directly from your computer into the message box instead of using the Attach button. Open your file browser in one window and your Outlook message in another, then drag the file from the browser into the message area. It attaches automatically.

This method works on Windows and Mac. If drag-and-drop doesn't work, your browser may not support it — try using the Attach button instead. Some corporate networks also disable drag-and-drop for security reasons, so if it's not working, contact your IT department.

Frequently Asked Questions

Can I attach a folder instead of individual files?

No, Outlook doesn't allow you to attach a folder directly. You must select individual files. If you need to send multiple files in a folder, either attach them one by one, select them all at once in the file browser (using Ctrl+A or Command+A), or compress the folder into a .zip file and attach that instead.

What file types can I attach?

Most file types can be attached — documents, images, videos, spreadsheets, PDFs, and more. Some organizations block certain file types like .exe or .bat files for security reasons. If your file won't attach, your organization's email administrator may have blocked that type. Try converting it to a different format or contact your IT department.

Why does my attachment show as a link instead of a file?

If you attached a file from OneDrive or another cloud service, Outlook may have inserted it as a link instead of a copy. This is usually intentional — it means the recipient sees the latest version of the file. If you want to send a copy instead, download the file to your computer first, then attach it the normal way.

Can I attach files to a meeting invitation?

Yes. When you create a meeting invitation in Outlook, the Attach button works the same way as in a regular email. Click it, select your file, and it attaches to the invitation. Recipients will see the attachment when they open the meeting details.

What's the difference between attaching and inserting a file?

Attaching a file keeps it separate from the message body — recipients download it as a file. Inserting a file embeds it into the message itself, usually as an image or object. Use Attach for files you want people to download and work with separately. Use Insert if you want the content to appear directly in the email.