Licensing agreements are between the photographer (the Licensor) and a client (the Licensee).  They set out the agreed terms under which a client can use (the Licenced Use) the photograph(s) they are licensing.  The agreement usually specify the Terms of the licence such as the Licensed Use, the Licence Fee, the Duration of the Licence, mandatory requirements such as a Credit, and any restrictions e.g. no commercial use without prior written permission. A thumbnail of the licensed image(s) should be atached in a schedule.

It’s common to include a warranty that the image(s) is free from encumbranes and third party claims; and an indemnity against a breach of the terms by either party.  The agreement will be binding when signed by both parties.