To copy an offer letter template and save it as a new template, go to Your Account > Account Details and then select Edit next to the template you want to edit.
Then click on the Copy to New button.
This will copy the offer letter template and add "Copy" to the Name field. You can then completely rename the template by selecting the text in the name field and editing it or typing over it. Make any edits you want to the Offer Letter Body and then click on the Save New button to save your new template.
Tip: Save hiring managers time by inserting any of the field names listed on the right hand side of the Offer Letters page into your offer letter template. The field names will populate when you create a new offer letter to send to an applicant. Make sure you enter them exactly as they appear. You can copy and paste them right into the template in order to make sure you've gotten the right formatting.