I can’t download apple support on my device please update on own my device..!

An iPhone 6 Plus isn't capable of 13 or above. Try downloading it to a newer unit on the same Apple ID first.

(224051)

The iPhone 6Plus cannot update further then iOS 12.5.6 due to hardware limitations.

The phone is considered obsolete, if you want to run newer apps you will need to get yourself a newer phone