General beginners question about Ionic Cloud auth

I’m new to web developing in general and I don’t really now anything about backend, so this might be obvious for you.

Say there is an App with a PHP Backend and a sql Database for User and Other Data (group of users etc).
As I understand it, authentification has 2 general roles:
-Loggin in the User, so the app can identify him and serve him the right content
-Secure the Api calls, so they can only be made from the app

Now if you want to archive the second one with ionic cloud, how do I secure the calls to my sql database and php backend with the auth from ionic cloud?
Can I use the token generated to make secure api calls to my own backend?