Fixed templates (often system or library defaults) ship with a defined set of fields and scoring tuned by the author. They’re ideal when you want a proven structure—Oura and Renpho templates are examples tied to device data.
Custom templates are ones you or your team create in the Template Builder: you add fields, set point values, conditions, and category mapping. Forking an existing template is the fastest way to customize.
Both types assign the same way in Profile; the difference is who controls the schema and updates.
Tip: Start fixed, then fork once you know which fields you actually fill every day.