Give your child something small and ask them to take it to a specific person in another room.
Name the person and the object clearly, then let them go alone. Ask the receiving adult to say thank you properly and make eye contact.
Do it in both directions so messages travel back as well as out.
Delivering something requires holding a person and a goal in mind across a room, then completing a social exchange at the other end. It is one of the earliest tasks where a toddler acts as a genuine link between two people rather than the centre of attention.