It is used to express that someone has added another person to a list, group, or platform, such as:
* A contact list: "Te agregué a mi lista de contactos." (I added you to my contact list.)
* A social media group: "Te agregué al grupo de WhatsApp." (I added you to the WhatsApp group.)
* A game or app: "Te agregué como amigo en el juego." (I added you as a friend in the game.)
It can also be used more generally to mean "I included you."
The verb "agregar" can also be translated as "to add" or "to include" depending on the context.