NauticEd has a whole suite of sailing endorsements that are offered and administered at the sailing school by the sailing instructors.

Below is a view in the instructor's portal. When they pull you up as a student in the software, they are presented with all these check boxes. Once they run you through a specific training workshop, they will check off the box. This will automatically post a sailing endorsement to your resume for all to see. You can see that NauticEd schools are a great resource for learning.

Note that endorsements are specialized workshops specifically set up for that skill. They are NOT just a general sign-off during a general assessment.