A customer requires a proforma invoice

Welcome to the QuickBooks family, @evelyn9.

I can show you how you can provide your customers with a proforma invoice. Let's first use the Custom form styles feature to create the template.

I have a few easy steps you can follow to perform this task. Here’s how:

1. Click the Gear icon, then choose Custom Form Styles. 
2. Click the New style drop-down and pick Quote from the option.
3. Tap the Design tab to enter the template’s name.
4. Navigate to the Content tab and select Content to view the form’s complete details.
5. Click the header and access the Form section to change the name from Quote to Proforma Invoice.
6. Press Done.

Additionally, I recommend the following resource, which contains a further guide about customising sales forms: Customise invoices, quotes, and sales receipts in QuickBooks Online.

Let me know in the comment section below if you have any other questions. Have a great day ahead.