CORE automatically watermarks files for all users who are viewing files in the system. The only reason a user would not see a watermark on a file is if watermarks were turned off for that user, which is usually a rare VIP situation.
TLDR: The watermark is added automatically so you don't have to.
Below is some general information about watermarking in CORE:
The user role defines the watermark, and every user will see a watermark on all files that they view in the CORE system.
A production watermark overrides a user’s watermark for any files on that production. Which means if the production watermark style is different from a user's default watermark style, the production watermark style is what they will see on all files associated with that production; whereas, their default watermark will appear on all other files.
When you share a package, the recipients' default watermark will be applied to that package when they view it in the player.
When a user sends a package with the Download Settings = Download WITH Watermark, they can customize the downloadable watermark layout for the recipient user, though they can’t change the name or information contained within the watermark.
User Default is the watermark layout style defined by the recipient’s user role
The recipients can download the watermarked files , but cannot change the watermark or the proxy file resolution defined by the sender.
CORE does not watermark the original files. When downloading watermarked files, a user can download only proxy files with the watermarks defined by their user roles.
High res proxies are 1920x1080 or up to 2000x2000 for images
Low res proxies are 1280x720
If a user has the permission to Change Watermark
When downloading from a Package or File Search, the user can change the watermark that is applied to downloaded files, either applying their default user designation or creating a custom label that will appear.
The user can also apply a Group user list to watermark a set of files - This comes in handy when downloading files for group distribution, i.e. scripts distribution, presentation copies for meetings, etc.