How do I purchase assets to use for something I'm developing for a client?

I need to purchase some videos and images to use to develop a video for a client. The end product will be displayed in the client’s lobby.

What is the type of subscription I need to purchase?
Do I need to continue my subscription for as long as the client displays the video in the lobby?
What happens if the client decides to show the same video on his website or on Youtube?

So far, there’s no problem.

You need to keep the subscription till the project is live ( When they start to display the video )

It will be probably taken down due to license issue. You will need to submit few documents.