I would like to know what is the difference between the two categories that I have to choose when I register an “application” (this term also applies to the “tab” page “). Thanks
Er, one application that should be installed as a tab on a Facebook page, and the other is a canvas application available at apps.facebook.com/appname. The documentation covers two types of applications quite clearly:
Canvas apps: https://developers.facebook.com/docs/guides/canvas/
Page Tab: https://developers.facebook.com/docs/appsonfacebook/pagetabs/