This feature works differently for Android and iOS.
Android
Steps to follow:
On your Android phone or tablet, open the Settings app;
Scroll down and tap System Languages & input;
Tap Advanced Autofill service Autofill service;
Tap Google OK;
Tap Back Settings;
Make sure Use Autofill with Google is turned on;
Confirm that the account listed under "Account" is the one you want to use.
Important:
These steps may vary on your device. You can also search your settings app for “autofill service” to go to this setting directly.
Tip:
Signing in to Chrome and Android with the same Google Account ensures you’ll always have access to your saved passwords.
Create & save strong password:
When you create a new account on an app, Android can suggest and save a strong password:
On your Android phone or tablet, tap the password creation field.
Just above the keyboard, tap Passwords Generate Password and save to your Google Account.
Complete your username and click Save password.
Sign in with the saved password:
If you saved your password for an app previously, Android can help you sign in.
On your Android device open the app you want to sign in to (you might need to go to the app’s sign-in page);
Tap the username field and select or type your username
Tap the password field;
Above the keyboard, on the right, tap Passwords Pick a saved password.
If the Passwords section doesn’t appear, press and hold the password field. Then, tap Autofill Pick a saved password. Then tap the name of the app you want to sign in to.
iOS
When the user successfully logs in, the app will ask him whether he wants to save his password or not:
If the user decides to save the password, then, the next time he tries to log in, the app will ask if he wants to use the saved credentials to log in:
For this to work, the user must enable "auto-fill passwords" option and allow filling information from "iCloud Passwords & Keychain" in their phone's settings here:
Settings -> Passwords -> Password Options
Users can also see their saved information in the Settings -> Passwords section and if required, they can remove any saved credentials.
Credentials will be listed under the domain "atommobility.com".