Instead of receiving a refund, I would prefer to apply the amount of overpayment toward next year's taxes due--how can I do that?

To add, change or delete a current year federal tax refund to next year's taxes before you file your tax return -

Click on Federal Taxes (Personal using Home and Business)
Click on Other Tax Situations
Under Additional Tax Payments
On Apply Refund to Next Year, click on the start or update button

Or enter apply federal refund to next year in the Search box located in the upper right of the program screen. Click on Jump to apply federal refund to next year

The amount applied to next years taxes will be shown on Form 1040 Line 36