If I license an asset for a client, and use the asset in e.g. packaging designs and then my client wants me to send the asset (image) to them, so they can use it for their own purposes (for producing other marketing materials etc.). Do I have to send the Licence Terms to my client, that they sign the Terms, or what?
Your client that licenses the images/videos can re-use the assets for their own use. Just like images that can be used in many different print and web applications as long as it is for the same licensee.