When creating and editing Assessments, Goals, Admin Users, and Students, you can apply Tags (more information here) to help you identify these objects. This allows you to group similar things together and more easily search for them (both on the administrative side, as well as in the reports).
To add a Tag, click into the Tag textbox. A list of available tags will be displayed for you - click on any displayed tag to apply it to your object. Otherwise, begin typing the tag you're interested in - the list of available tags will be limited to tags that match what you've entered:
If you don't see an already-existing tag that you want to use, enter the tag you want and hit Enter.
Once a tag has been selected, it will show up inside the Tag textbox:
Be sure to Save the object (Goal/ Assessment) or click the Update Tags link (Students and Admin Users) to save your Tags.
If you want to remove a tag, just click the "x" at the beginning of the tag name and be sure to save.