The IRS will take care of that for you. You do not enter anything on your tax return about it. If you owe the IRS, they know it and they will offset your refund for the tax you owe. You will receive a letter from the IRS a few weeks after they do that.
@ls22345 wrote:
Can I still file electronically?
Yes, file normally. If your return claims a refund, the IRS will keep enough to satisfy the debt, and pay you the rest, although it may take a little longer for processing. About 4 weeks after getting whatever is left as a deposit, the IRS will send a letter confirming that your refund was adjusted and your debt was cleared.
If your refund is less than the debt you owe, you need to keep making your on time payments. The refund will be applied to the debt, but it won't reduce the amount you are required to pay, but it will reduce the number of remaining payments.