The person you like has a birthday. Should I send a circle of friends? In what capacity?

Never send a circle of friends! Because you have no position to send a circle of friends! You can like her, she may or may not know, but you won't get her approval after all! If you make a circle of friends, you may not get her favor, but you will make her angry and disgusted with you. So, you can send her WeChat directly and wish her a happy birthday!