You can use the closed captions button in Google Hangouts to turn closed captions on or off during a video conference. Please note that captions are generated automatically so there may be errors. This feature is currently only available in English.
See more from Google's guide to this feature.
Consider the following quick tips as you work to make your course accessible in an online format:
Read through these suggestions and resources by Aimi Hamraie, "Accessible Teaching in the Time of Covid-19": Aimi has suggestions for options depending on the type of course (lecture-based, discussion-based) and the type of assignments (projects, presentations, papers and tests...).
Check out this resource from Sheryl Burgstahler at the University of Washington: "20 Tips for Teaching an Online Course" (also available as a PDF, below, and as a video!).
The Canvas Accessibility checklist is available at http://bit.ly/gc-canvas-accessibility. Run through this checklist to make sure your Canvas course is as accessible as possible.