COMPUTER
In the left column, click the team or group.
In the feed, click the paper clip icon.
In Posting To dialogue box, select additional teams or groups to post file.
TIP: In the right column of the team or group, posted files automatically save to the Files section.
APP
In the bottom tray, tap Teams/Groups.
In the feed, tap, "What are you up to?"
Tap paper clip Attach File/Document.
In the top right, tap Next.
Select additional teams or groups to post the file. In the top right, tap Post.
TIP: In the right column of the team or group, posted files automatically save to the Files section.