Detailed techniques on “how to block” annoying calls and texts for Apple iPhone or Android smartphone systems are shared by PC Magazine:

https://www.pcmag.com/news/how-to-block-a-number-on-your-smartphone

There are all sorts of reasons to block a number: an ex who won’t stop calling, telemarketers who can’t take a hint, scammers, or an aunt who wants to see why you’re still not married. When your phone has buzzed one more time than you can take, you know it’s time to block that number. But how? Here are the steps to take by popular operating systems and carriers.  The first way to reduce the number of unwanted calls coming to your phone is to put yourself into the National Do Not Call Registry. On DoNotCall.gov, you can register your phone number