STEP 1:
If you want to update your php version.
Then go to php offical site https://www.php.net download your desire version from there.
STEP 2:
A zip file will be download, extract it.
STEP 3:
Then put it into your apache local server like (Xampp, Laragon, Wampp etc) in php folder.
STEP 4:
a) goto search bar of the window
b) search "environment variables"
c) goto "Enivronment Variables..."
d) In System Variables got "path" variable
e) Add your php folder path that you added before in apache local serve
NOTE !
If you are using multiple php versions at a time
then make sure that version you want use keep that version path at the top or first from other php versions
Boom!!!!!!
It's DONE.