Akshit Chauhan generally first you create website and then with the link of website the android web view is created from different resource like android studio, go native but you saying apk to php if it's your apk then it's converted from website which you made in php so you must have the php code already as You cannot convert a PHP website to a native Android app. What you can do is to load the website in your app using a WebView or build the app from the scratch in order to enjoy the native-feel.
Or you have created apk then load the web view which can be easily converted in php if you have any knowledge and working experience in php
Is it your app (you mentioned "convert my app")?
If it was your app you should already have the source code of the app. Then you can rewrite it into PHP code (there may be some incompatibilities), if you understand PHP code.
As I understand it, even though there may be tools out there for the purpose, porting tools always come with a glitch, you may end up just getting nothing usable in the end.