I invoiced a customer w a special offer which ended Feb29. Now it's March. I want to void the invoice but can customer still pay and will QB accept the payment?

Did your offer demand payment by end of Saturday night or not? If this customer always enjoyed extended terms and you take that away they might never return.

Voiding an invoice will not prevent them from paying the original amount - it just will not be assigned to anything.  You can EDIT and resend corrected invoice - no need to void and start over 

Hi John,

This is a new customer, so they are not used to extended offers. The February offer was receive something extra valued at $100 when customer pays the invoice in February. Now it's March and that offer is done and over, but from your reply I cannot control turning off their ability to pay.

I will have to edit and resend.

In future, what is a better way to handle this same situation, when an invoice is time sensitive? I am new to QB and there may be features of invoicing I am not aware of. I don't know how late fees work, but the deadline is a certain date, not a date range (like pay within 30 days).

Thank you!

Thanks for getting back, jpatselas.

In QuickBooks Online (QBO), you can take advantage of applying terms option. You can setup a specific Net which refers to the number of days before the expected payment.

You can either set a term for all of your customers or only for a specific one. 

Terms apply to all customers:

1. Go to the Gear icon.
2. Choose Accounts and Settings.
3. Click the Sales tab.
4. From the Sales form content, click the drop-down arrow beside Preferred invoice terms and choose your desired term.
   
5. Click Save, then Done.

Terms apply to one customer:

1. Open the invoice.
2. From the Terms drop-down, choose your desired term.
3. Click Save and close.

I've got you a guide on how to become more familiar with managing terms in QuicBooks Online (QBO): How to Adjust Invoice Payment Terms in QuickBooks Online.

On the other note, I'll show you how to manually enter late fees on invoices. Learn more about this through this article: How to enter late fees or finance and service charges on invoices.

You may also consider applying the late fees automatically to your customers invoices.

Here's how to turn this on:

1. Click the Gear icon.
2. Select Account and Settings.
3. Click the Sales tab on the left panel.
4. Click the pencil icon in the Late Fees section.
5. Check the box to turn it on.
6. Enter the Type, Amount, Frequency, and Grace Period.
7. Click Save, and then Done.

You can also refer to this article to learn more about applying automatic late fees in QuickBooks Online.

For additional questions, just let me know by leaving a reply below. I'm always happy to assist. Wishing you well.