Created as Unit 1, Unit 2, … You can rename them afterwards.
Rename a unit to whatever you call it — “Flat 3”, “Shop A”, “Penthouse”. Renaming moves its tenant with it.
Each person who uses this app signs in with their own Google account and gets their own workbook — nothing is shared between accounts. Don't share your workbook file directly in Drive; use "Choose a different file" instead.