Provider
I think that they are coming from your Provider / Telco. Some of them can push ads. The last time I had this was when I was visiting India and had a local SIM. If they do push ads, you can see a button to disable them in the Networks section.
I can't be more specific as I dont see that button right now because my Provider does not push ads.
Manufascturer
The phone manufacturer can also push ads, such as Samsung. In which case you can turn off the notifications.
- Go to Settings -> Notification -> App Notifications
- Search for "push"
- You can probably disable all of them
Services
You can also get ads / notifications from Store, Wallet, Themes etc. You can search for them in `App Notifications' as above and disable them.
Customisation Service
- Goto Settings
- Press on your name
- Press on Security and Privacy
- Press Customisation Service
- Slide the
Customise this phone
to off.
Note not all of these settings will be on all phones or providers.