The first time you attend a Zoom meeting on an iPhone or iPad, you'll need to download the Zoom app from the App Store. Here's how to do that. You'll start by tapping the meeting link, either in an email or on a web page (depending on how you received it). That will open a Zoom page in your browser, like this (Safari on iPhone shown here):
You'll start by tapping the button "Download from App Store," which will take you to the Zoom application's page in the App Store, shown here.
Tap the "Get" button (the little cloud with arrown just under the icon). You'll be prompted to go through the usual application installation process. At then end, you can tap the "Open" button to start the app, which will show you its initial login screen:
Now, you can, if you wish, use the "Join a Meeting" button (but you'll need the meeting ID). An easier way is to go back to the page in your browser (the page that showed "Join Meeting" and "Download from App Store". This time, you'll tap the "Join Meeting" button. The browser will prompt with "Open in Zoom?"
Tap "Open", and now the Zoom app will open and prompt for your name:
Enter your name, tap "Continue", and you're in.
On first run, Zoom will ask for access to your microphone. It's OK to tap "OK."
It will also ask to send notifications. This is usually OK, but not necessary to join the meeting.
And you will need to make an audio choice. If you have a good WiFi connection, you can choose "Call using Internet Audio." You can also dial in using cellular (but if your WiFi isn't good enough for audio, it's probably not going to be good enough for videoconferencing.)
And finally, you're in the meeting. Note the Mute and Start Video buttons near the bottom. Typically the video will be off when you first join (and if you're not the presenter, it's a good idea to leave it off).
Happy videoconferencing and happy folding!