You must have a bookkeeping system that includes a written document on what is owed to you. Whether it’s a one-time invoice or a payment plan, put it in writing!
To make your life easier, create templates for contracts, and have it reviewed by legal counsel to make sure it complies with federal and state laws.
And take advantage of software benefits. QuickBooks has a “batch” invoice option that can help cut down on the time it takes to do your monthly invoices.