This page contains information on encryption in Zoom.

The shared content of your Zoom meeting is encrypted by default with 256-bit AES-GCM encryption. The audio track of people participating over the phone is encrypted until it leaves Zoom's servers and continues to transmit over the phone network.

For further protection, the host can turn on end-to-end encryption (E2EE). In this case however, participants will not be able to join the meeting via the browser.

In the meeting, you can recognize the encryption by the icon at the top left of the Zoom window:  

For more information see Zoom documentation.