Assigning leads to sales territories
Key Takeaway
Rules don't place leads in territories, so you assign each lead by hand from its "Assigned Territories" related list. In Lightning Experience, you can pick territories only from the Active territory model.
Sales Territories groups accounts and leads into territories so the reps assigned to a territory can see and work those records. Assigning users or roles to a territory controls who can access the accounts and leads in it. You give a lead its territories by hand from the lead record, which ensures coverage for leads that need a specific territory.
Territory models
A territory model can be in one of three states: Planning, Active or Archived.