landing page ? website?

I have no idea how to say this. but i saw it on someone's zoom and i want to figure out how to do it., I schedule meetings all day, and most of the time, I am ok with name, email number, and all of that stuff. but when I have a trainee who is doing the same stuff, and instead of a scheduled meeting, they want to do it right now. I saw a link that I clicked on, and it went to a page and said for an instant meeting, click here, and it put you in the room. What is that called? how do i do it?