Birthday cards are special greeting cards designed to celebrate a person's birthday. They often feature colorful designs, cheerful messages, and sometimes even images of balloons, cakes, or gifts. People typically write personal notes inside the cards to express their good wishes and love for the birthday person. These cards can be purchased from stores or made at home, allowing for a personal touch. Many people enjoy collecting birthday cards, and some even keep them as mementos. Sending a birthday card is a common tradition that helps to make the birthday celebration more memorable and meaningful.