How to change a refund of overpaid tax to next years estimated tax on the federal return and the state return?

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 Schedule 5 Line 66 and flows to Form 1040 Line 17

To apply a state tax refund to next years state taxes there will be a similar procedure in the state tax return program.