Is there way to add multiple people to a tag at once?
Yes, If it's on Messenger, you can add up to 10 people to a tag.
You need to tick the checkboxes and then to your right, you'll see a Tag all button.
You can do the same to tag your friends on your profile as well as the groups you are in.
You can do the same to tag your friends on your profile as well as o groups.