Add an attachment to a task
Select the task to open the task window.
Select Add attachment.
Select File to attach a locally stored file, select Link to include a link, or select SharePoint to attach a file from a SharePoint site.
Navigate to and select the file you want to attach, or enter the link information.
When attaching a file, you can upload the file to OneDrive for the plan, or you can browse to find it if you've already uploaded it. If your file isn't located on OneDrive for the plan, you can add a link to it instead.
The first time you attach a file, photo, or link to a task, that attachment becomes the task's preview picture. It's shown on the Board, and offers a quick way to identify the task and get to work. Want to change the preview picture for a task?