Open the Google Play Store app
At the top right, tap the profile icon.
Tap Manage apps & device.
Tap Manage, then find the app you want to update automatically.
To open the app's "Details" page, tap the app.
On the app's "Details" page, tap More
Turn on Enable auto update.
When updates are available, the app updates automatically. To turn off automatic updates, turn off Enable auto update.
Tips:
When some apps get updated, they require new permissions. You may get a notification that asks whether you accept the new permissions.
To update an app, you may need to restart your device.
To search for a specific app, tap Manage apps & devices > Manage.
If the app has an update available, the "Update" button appears on the app's "Details" page.