How to update my phone iOS 13 or 14

It depends on which model iPhone you own. If you are asking about iOS 13 or 14, I suspect you have a phone lower than iPhone 6s, which is the oldest phone which is capable of running the current iOS 14. You cannot get iOS 13 period. iOS 13 is no longer the current iOS. iOS 14.0.1 is the most up to date version you can get.

Go to Settings > General > About > Model

What does it say?

Please don't leave me guessing which iPhone you have and just tell me which is it? That may help me give you a good answer to your question. Thanks.

Axel F.