Select Who Can Work in Email Template Builder

To let other users create templates with Email Template Builder, give them the Access Drag-and-Drop Content Builder permission. Any user that can send can insert email templates made with Email Template Builder into an email or list email.

Required Editions

Available in: Lightning Experience for email templates created in Email Template Builder and Email Content Builder
Available in: Professional, Enterprise, Unlimited, Performance, and Developer Editions.
Available in: Account Engagement Lightning App for all Account Engagement editions
User Permissions Needed
To create permission sets: Manage Profiles and Permission Sets
To assign permission sets: Assign Permission Sets
  1. From Setup, in the Quick Find box, enter Permission Sets, and then select Permission Sets.
  2. Create a permission set, and then select System Permissions.
  3. Click Edit, choose the Access Drag-and-Drop Content Builder permission, and click Save.
  4. If necessary, click Manage Assignments to assign the permission set to users.