Create api for connect php file from hosting

hi i need help about if its possible to connect my app to the hosting for edit values from my file php. its because i am creating two apps. the first app only reader database from php and mysql that are in the hosting. and the second for modify the values like a editor for changing the values from php file. so its possible to create an api for editing files php changing the values for the first app that only read the values from hosting?.

Here you have an example of mySQL and php. In this case, used to register and login. But it can help you to understand the concept: