You can add captions to your Page’s video to make it accessible to a broader audience. You can automatically generate captions and edit them, write them yourself, or you can upload a SubRip (.srt) file.
To add captions to your Page’s video:
From your News Feed, click Pages in the left menu.
Go to your Page.
Click Photo/Video at the top of your Page’s timeline, then select a video from your computer.
Once your video has been uploaded, click Subtitles & captions (CC) in the column on the right.
Once your video has finished uploading, select whether you’d like to auto-generate captions, write them yourself or upload a SubRip (.srt) file.
Click Next, then click Publish.