The host of a Zoom meeting can turn on the closed captioning option and can assign this role to a participant. If you have been assigned this role, you will see a Closed Caption icon in the video controls at the bottom of your meeting window.

Visit the vendor's help documentation and look for the section Assign a participant to type closed captions for instructions to enter captions manually.

The following video from the Zoom Learning Center gives an overview of Accessibility features in Zoom.