Why can’t I download Facebook and some social media’s

iOS 12.5.7 is the latest iOS security update for iPhone 6 Plus.

👉 iPhone 6 Plus can’t be update to a higher iOS (13 and later). 

If you have an outdated iPhone that cannot be updated to iOS 13 or later, many apps will not be able to download.

Outdated iPhone no longer meets the requirements for many apps.

Most apps require iOS 13.4 or later.          

Except for these social media apps.

WhatsApp requires iOS 12.0 or later. 

Snapchat requires iOS 12.0 or later.

Considering a newer type of iPhone?

Read this before you buy a newer type iPhone.

As already observed, your iPhone is too old to use an iOS version required by many newer apps. You may find, however, that you can still log into the web version of those sites using a web browser on your iPhone.