I've got you, @Hannah48. 

Changing the customer label is accessible exclusively in the United States. As a solution, if you subscribe to other regions, you can still convert Customers into Donors by customizing the sales forms. 

Go as follows: 

1. Go to the Gear icon and choose Custom form styles. 
2. In the New style drop-down, choose specific sales forms. 
3. Select the Content tab and hit the first pencil icon. 
4. Change the Form names, then click Done. 

You can also make the template as default. For more information, see this link: Customize invoices, estimates, and sales receipts in QuickBooks Online.

Use the template you created while generating the transaction. Please remember that the Donor label will appear only when previewing and printing the form. 

Go as follows: 

1. Create a sales transaction by clicking the +New icon. 
2. Complete the necessary details. 
3. Click the Customize tab on the bottom part and pick the appropriate template. 
4. Hit Print or Preview. 

Moreover, check out the following articles below on how to track donations to your organization and manage accounts receivable transactions:

• Track funds you receive from donors in QuickBooks Online
• Invoices and payments FAQs

Let me know if you have other QuickBooks questions. I'll keep an eye out for your reply and look forward to chatting with you soon. Take care!