Welcome to the Community, dave203.

Setting the due date to the end of the month isn't possible when using the 30 days term. I'll share a method so it shows the last day of the month.

Here's how:

1. Go to the Gear icon, select All lists.
2. Click Terms, then New.
3. Enter your desired name, In the Due by certain days of the month enter 31.
4. In the next box Due the next month if issued within input 31.
5. Once done, hit Save.

I've also included the following articles below to help you manage your sales form:

• Customise invoices, quotes, and sales receipts in QuickBooks Online.

• Add, customise, or remove logos on sales forms.

Let me know if you need further assistance about managing terms in QuickBooks Online. We're always available anytime.