Thanks for reaching out to the Community, businesscycle.
 

You can switch between different invoice templates from your Custom form styles page.
 

Here's how:

1. Use the Gear (⚙️) icon.
2. Choose Custom form styles.
3. Find a template you'd like to set as your default.
4. Under its ACTION column, click the Drop-down Arrow (▼).
5. Select Make default.
   

In the event you need to create a new template, simply click your New Style ▼ button and pick an appropriate type.

I've also included a detailed resource about working with custom form styles which may come in handy moving forward: Customize invoices, estimates, & sales receipts

I'll be here to help if there's any additional questions. Have an awesome Wednesday!