What does it mean to enable SMS blacklist and mobile phone whitelist?

White list means that only the contacts or numbers in the white list can call your phone and text messages, and all other phones can't call your phone and text messages.

Blacklist means that only the contacts or numbers in the blacklist can't call and send your messages, and all calls except the first time can call and send your messages.

These two functions generally do not need to be used at the same time.