QBO for non-profit

Hello,

Our non-profit organization provides services to clients. I want to send an invoice to an organization where we provide services. Right now, I see "Donors" instead of "Customers." How can we create a "Customer" object that we can specify as "an organization we bill." I was starting to use Projects in QBO Plus, but no "Customers" field, only "Donors" and no "Customer/Project" field in the bank feed. What is the right way to invoice our customers and record all our projects (program) in QBO?

I need help from the community.