"All Choices" option for Sharepoint Library Choice Column

maddinsdt This is not possible using SharePoint out of the box design capabilities.

If you are creating a new view with filters, you can add two conditions in filters using "Or", like: 

OR user has to select the two choices while filtering, one for documents under "Choice 1" and one documents for "All Tailsigns".

OR you can customize library form using Power apps, add "All Tailsigns" choice from Power apps and when users select this option, it will automatically select and save all choices in the library.

Please click Mark as Best Response & Like if my post helped you to solve your issue. This will help others to find the correct solution easily. It also closes the item. If the post was useful in other ways, please consider giving it Like.