Tags can be used to classify goals and filter goal lists, either functionally (e.g. "Performance goals", "Development goals", etc.) or chronologically (e.g. "Q4 2018", "Q1 2019").
To keep things organized, goal tags are centrally managed. As an admin, you can create or modify goal tags under "Admin settings" > "Account settings" in the goal tags section.
Once created, you can assign one or multiple tags to each goal when creating or editing a goal.