The good thing about QuickBooks is that you can save your favourite invoice/sales receipt templates. This makes it easy for when you want to use those templates in the future. For example, if you have a custom template, you can access and edit it by clicking the Gear icon > Custom Form Styles > before clicking New style, you can check to see the templates you already have on the Custom Form Styles screen. Otherwise, you can simply click on New style to create and save another template. 

You can then utilize these templates when creating a sales form in QuickBooks. For example, when creating an invoice, click on New (+) > click on Invoice > once the invoice screen comes up, click on Customize at the bottom of the invoice screen > here you'll see all the templates available to you. Once you click on the template, the customization options on template will automatically apply to your invoice and other sales forms you may create when you manually select the template of choice. Here's a helpful article with more info about: Customize invoices, estimates, and sales receipts in QuickBooks Online.

Let me know if this info helps clarify things for you. I'm here in case you have any other questions.