The Home Equity Line of Credit (HELOC) interest should be on form 1098-Mortgage Interest. Call your lender and find out when they will be mailing forms or if you have an online account, see if you can access it.

See Can I deduct my mortgage?

To enter, click on Where do I enter my 1098 mortgage interest statement?

For Home Equity Line of Credit: If you take out a home equity loan, your interest payments may qualify for a deduction in addition to your mortgage interest. To qualify, you must have obtained the loan after Oct 13, 1987 and it must also be secured by your home.

For tax purposes, only the balance of the loan that is the smaller of $100,000 or your equity in the home qualifies for the interest deduction. Your equity is equal to the amount you could sell the home for minus the amount you still owe on the mortgage.