Hi!

I Can't activate the app.

 I see message:

"To switch to live mode, you must provide a valid Privacy Policy URL and data deletion information. This information can be updated in the basic settings in the app bar"

Should I create a page with the agreement? What should be written there?

@alex7070
You should check facebook docs/help instead. Privacy policy as well as Terms & conditions page must probably exists in order to be able to use facebook services.