YouTube has provided a way to auto-create caption files from videos you have uploaded. However, the accuracy of the auto-captions is not reliable. Therefore, you need to go to the video manager within your YouTube Channel, and manually edit the captions. Because of this, it is recommended that you use the auto-caption feature for shorter videos.
To add or edit a captioning file, you must be the owner of the video and have the video uploaded to YouTube.
Automatic captioning works best when the audio is clear and easy to understand. (E.g., background music or speaking in an accent can affect accuracy.)
The automatic captioning option may not be available for all videos.
If you haven’t already, sign in and upload your video to YouTube.
In the top right corner, click on your user profile and select Creator Studio from the dropdown menu.
This will bring you to your Creator Studio Dashboard where you can select which video you’d like to add captions to.
Click the Edit drop down menu from the video you wish to caption and select Subtitles/CC
Click on the Create New Subtitles or CC dropdown menu and select your preferred language
In the Subtitles and CC tab select the automatic captions option (e.g., English (Automatic) )
It takes some time for YouTube to process your video therefore, it may take around 10 minutes or so before the Automatic option shows up.
Test the captions for accuracy by playing the video and reviewing the text concurrently. To edit the captioning file, select the line that needs repair in the captioning editor text box.
Use the Add below and Remove icons to add and remove captions as needed.
For additional information about adding captions to your YouTube video, consult the official documentation.