Ad block trick on Android

Forgive my ignorance of I get the details wrong. IT isn't my field

A while back someone posted a comment that instructed how to change Android settings so data is filters to block ads. I copied a (I think?) server address and pasted it somewhere in my phone settings and I haven't seen an ad in apps since.

I thought I saved the instructions but not I can't find it. Can someone tell me what I did? I'd like to …

ad android privacy