Hi.

Are you looking for a print template or adding a new template for invoice print out or for a pre defined template from which you can create a new invoice record ?

If the later is the case means, such an option is not there by default, in sales there is quotation templates, from which user can create new records using this template.

if you need the same, you have to customize and make it possible or just create a draft invoice and name it as Template and duplicate/copy this while you need to create a new invoice.

If the question is about a print template, you can add new template from code.

Reference:  https://www.youtube.com/watch?v=pIevsbkoq-E

Thanks