To stop ads on an Android phone, several effective methods can be used:

1. Use Private DNS to block ads system-wide:

   • Go to Settings > Connections or Network & Internet > Private DNS.
   • Enable Private DNS and set the provider hostname to "dns.adguard.com" or "dns.dog.guard.com" (these services block ad domains).
     This blocks many ads in browsers and apps without needing additional software.

2. Disable pop-up ads in browsers (e.g., Chrome):

   • In Chrome, go to Settings > Site settings > Pop-ups and redirects and turn off pop-ups.
   • Also, enable blocking of intrusive ads in Chrome settings.

3. Manage app notifications:

   • Identify apps sending ad notifications by going to Settings > Apps.
   • Select the app and disable its notifications to stop ad pop-ups from those apps.

4. Uninstall ad-serving or suspicious apps:

   • Remove apps that frequently show ads, as they often serve ads to generate revenue for the developers.

5. On Samsung devices, disable personalized ads and notifications through Samsung Account Privacy settings and Notifications menu.

6. Consider using browsers like Firefox for Android with ad-blocking extensions such as Ghostery to block ads on websites like YouTube and Facebook.

These approaches help reduce or eliminate most unwanted ads on an Android phone both in apps and browsing environments without needing to root the device or install intrusive apps.