how do I turn off the pop-up that says 'share board'?

[cc]

I do not see that it is a power-up, and cannot figure out where it came from.  

[Vishaal S]

Hi there, 

Welcome to Atlassian Community! 

From the screenshot, it appears that it's the core function with Trello boards, if you click on that share button from the board menu the pop-up comes in and you can click on the X simply to minimize the pop-up, Video grab for your reference: https://share.getcloudapp.com/4gurO2P2

Cheers,
Vishaal S | The Trello Team