I want to permanently remove facebook app from my iphone but i cannot

your details must not be correct. It says iPhone 6 running iOS 10. App Library is not available until iOS 14.

I'll assume that these details are incorrect.

review this

How to delete apps on your iPhone, iPad, and iPod touch - Apple Support

you can delete from the App Library by locating the app and tap/hold, select Delete App

or you can go to Settings > General > iPhone Storage > [app name] > Delete

If you still are unable to delete, check:

Settings > Screen Time > Content & Privacy Restrictions > iTunes & App Store Purchases > Deleting Apps

make sure that's set to 'Allow'

I have the Iphone 12 and if I press and hold the Facebook app in the App Library, it doesn't give me the option to delete the App, only Add it to the Home Screen or Share it. How do I permanently delete it?

no problem, glad to be of help!

Read the thread you posted in.. it's a very short thread and the answer should be in my first response..