Step by step
Open Services
Go to Services. Above the table you see Active / Inactive filters and chips for categories in use (Cut, Beard, Color, Nails, Massage, Other).
Filter by a category
Choose a category chip to show only services in that category.
Change a service category
Open a service → Edit → Category, pick another fixed option, then Save.
Check the list
Clear or switch filters and confirm the service appears under its new category chip.