In apps

iOS is a fairly closed operating system: Apple doesn’t provide many options to block ads outside of Safari. The first thing you need to do is enable DNS protection and select an ad-blocking DNS server (for example, AdGuard DNS):
Open AdGuard.
Go to Protection and enable DNS protection.
Tap DNS protectionDNS server and choose AdGuard DNS.
If it didn’t help, try using the browser version of the app or service (like YouTube or Facebook) in Safari. AdGuard can block ads there very effectively.
Downloading AdGuard To install AdGuard, click the file indicated by the arrow Select "Open" and click "OK", then wait for the file to be downloaded. In the opened window, drag the AdGuard icon to the "Applications" folder. Thank you for choosing AdGuard! Select "Open" and click "OK", then wait for the file to be downloaded. In the opened window, click "Install". Thank you for choosing AdGuard!
Install AdGuard on your mobile device