The word 收到 is formed by combining two individual characters, each contributing a key part of the concept. The first character, 收, primarily carries the meaning of "to receive", "to gather", or "to accept". The second character, 到, means "to arrive" or "to reach". When placed together sequentially, they create a cause-and-effect or resultative compound where 收 (the action of receiving) is logically completed by 到 (the arrival of what is received), thus forming the complete idea of "to have received" or "to have gotten something successfully".