“Unlock the Secret Weapon of Successful Authors: How Tagging Transforms Books into Bestsellers!”
In the event they do not allow for this kind of tagging, you can either ask them to share it on their page, or provide them with images they can use for sharing on social media. There’s no guarantee that a person you tag on social media will allow this post to appear on their page but it’s still worth a try.
On the other hand, tagging people on sites such as YouTube, X (Twitter) and Instagram works differently. When you tag them, it just gives them a private heads-up. Anybody else viewing that tag are the people already viewing that post.
