Are you uploading video to Canvas or is it hosted in a video hosting platform? This may determine what you will do.
There are some web based services that will transcribe for free such as oTranscribe
I haven't used it so I can't swear to how good the transcription is.
You can use services like these to get transcript files then attach them to your video in the hosting platform or post them to the page.
Some platforms have services built in, too. YouTube has their own builtin closed captioning. You can set your video to have closed caption turned on. Then you can view the transcript from the built in CC service. You have to do a weird little copy and past to actually have it in a file, but it works.
There are also tons of hacks of people playing their video and using an app on their phones to listen and transcribe for them. Works pretty well actually. I've done it for a few things that didn't need super accurate transcribing. For our mission critical stuff we pay for transcription via Rev.