invoices and payments

I am in need of help with creating invoices and payments for my business on a daily/weekly basis. My preference is to use bill.com and quickbooks for this task. This project should be a relatively small one - I anticipate needing to deal with less than 5-10 invoices and payments in total per week. Specifically, I need bills created from purchase orders and invoices created from sales contracts. Please see the attached po and sales contract for examples. Additional accounting and tracking tasks may be needed. Thank you.