Is it possible to customize headings in a Worksheet Template?

Yes, it is possible to customize a Worksheet Template by creating a duplicate of an existing System Default template within the Template Editor. 

The Template Editor can be found by navigating to (Reusable Library & Templates > Template Editor). 

Note: Data entered under one Worksheet Template may not transfer when switching to a different custom Worksheet Template. 

Find your templates
Go to Admin Center > Reusable Library & Templates > Template Editor. The Active tab lists your templates with their Name, Type (Core View or DFMEA) and Created and Updated dates. Deactivated templates are on the Inactive tab. System Default templates can be viewed but not edited.

Edit a heading

1. Create your own copy of a template. Either click the add button and select the template to copy, or open a template's three-dot menu (View Template Options) and select Duplicate. Enter a unique Name.
2. Open your copy's three-dot menu and select Edit.
3. Click the three-dot button on the column heading and select Settings. In a Core View template, do this in the Customize view. Headings can't be changed in the Re-arrange columns views. DFMEA templates have only one view.
4. On the Display tab, choose the Language and change the Header Display Text.
5. Click Confirm.

Remove a template you no longer need
Templates can't be deleted. Instead, open the template's three-dot menu and select Deactivate to move it to the Inactive tab. To hide it from the worksheet template dropdown, click the eye icon (Hide/Show Template in Worksheet dropdown). System Default templates can't be deactivated.