new address; forwarding address
Refers to the address one moves to; commonly used when notifying others of a change of address.
Notify the post office of your new address.
Please let me know once your new address is decided.
引っ越し先 is a more casual, everyday word for 'new place after moving', while 転居先 is slightly more formal and often used in official contexts.
Compound of 転居 (てんきょ, 'moving house') and 先 (さき, 'destination').