PHP is known popularly as a programming language for building back end website stuffs.
Android is capable of running PHP codes easily, no stress. This is tested and trusted.

If you want to run PHP on your local device, first of all install one of web servers with PHP from google play:

Those web servers are used to run php on android easily. 

Using KICKWEB SERVER: is an Android application known as a web server for running php on android. 

How to run php with kickweb server:
1. Download and install from playstore
2. Launch the web server
3. Scroll downward and hit "Confirm"
4. You'll be directed to settings, where you're told to turn on storage permission.  
5. Click "Storage and turn on storage "
6. Now, go back to the App and click the button at the top to run the server. 
7. Now, go to file manager or ES explorer. Look for a file named "htdoc".
8. Enter the file "htdoc" you will find a file named  "index.php"
9. Open it and write a simple php hello world 
echo "Hello World!"
10. Now, run the code with either firefox or chrome browser. 

That's all about running php on android. 
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