WhatsApp Block Feature

A: "Hi there!"

B: "Hi, how can I help you?"

A: "May I know how to block someone on WhatsApp?"

B: "You can either go to Settings >> Privacy >> Block List >> Add Contacts or enter a chat with someone you want to block and then press "Block"."

A: "Thanks."

B: "You are welcome."

A few moments later.

B: "Did it work?"

B: "Why isn't my message to you delivered?"