Short answer
HubSpot's KB: a default deal name, built from personalization tokens and static text, fills in when users create deals from existing contact, company, deal, ticket or custom object records. It needs Super Admin permissions. It applies to deals created manually on an associated record, so imports and workflows need their own naming. For workflows, set the name in the Create record action.
1. Deal defaults
Deal setup in my demo portal, where deal creation defaults live.
2. A naming pattern
Company name, product line and month is a common pattern; pick one and keep it.
3. Related
Default amount and close date.