The iOS device shows an open link or copy link option.

If the join link is in the in-meeting/in-webinar chat, the desktop and android device shows the leave and join options.

If you are already in an existing meeting and click a join link, it will prompt you to leave and join the other meeting.You can also join a test meeting to familiarize yourself with using Zoom, or join a meeting without an account. Otherwise, you will be prompted to download and install Zoom when you click a join link. Before joining a Zoom meeting on a computer or mobile device, you can download Zoom from the Download Center.