How to Add a Watermark to Uploaded Videos on Your ChannelWith YouTube Studio you can attach a channel watermark to videos already on your channel. How to Add a Watermark Using YouTube Studio Sign in to YouTube Studio.Open your channel menu and open Customization, then choose Branding.Click Add watermark.Pick the logo or image you want to upload. Confirm it meets the recommended YouTube video watermark size and file limits.Click Publish (or Update) so the watermark applies according to your display settings.