Short answer

HubSpot's KB: to reuse the layout of a drag-and-drop marketing email, open it and click File > Save email as template. Managing marketing email templates needs Super Admin or Design tools permissions.

1. The File menu

The email editor in my demo portal.

Email editor with File menu in the top bar — File (1).

2. Templates

See email templates.

3. Related

Exporting an email.

Sources

HubSpot Community question: Can I save/export existing emails as templates?
HubSpot Knowledge Base: Save marketing emails as templates

Save an existing marketing email as a template

Short answer

1. The File menu

2. Templates

3. Related

Sources

New field notes by email

Still stuck?