PHP is not recognized as an internal or external command in command prompt

You need to Go to My Computer->properties -> Advanced system setting

Now click on Environment Variables..

Add ;C:\xampp\php in path variable value

Now restart command prompt DONE!

Note: Make sure you run CMD via run as administrator

Add C:\xampp\php to your PATH environment variable.(My Computer->properties -> Advanced system setting-> Environment Variables->path (click on edit))

Then close your command prompt and restart again.

Note: It's very important to close your command prompt and restart again otherwise changes will not be reflected.