The new integration does not require any user to have an account.
Just click on the link to start Zoom video. It will then generate the link and any users in the thread can join.
I host online events, and I usually create a separate event link and share the link to the other hosts, speakers, or guests involved. In this case, I would recommend clarifying with the client if they want you to use their Zoom account to create the online events for them, or if you will be included in their business plan, or you need to create a separate account yourself. This way, you and your client are on the same page regarding hosting Zoom events.
I hope this helps!