How do I correct the entry I made to Mortgage interest paid in 2018?

Thank you for the answer. When I follow the instructions, the system gives me a screen where I can only add an additional entry, not edit the entry already  made. How can I delete the existing figure and enter the correct figure?

To revisit the Mortgage Interest section:

1.  If you're in the Forms mode, click Step-by-Step in the upper right-hand corner.

2.  Click Deductions & Credits across the top.

3.  Select I'll choose what I work on.

4.  Click Start or Update to the right of Mortgage Interest, Refinancing, and Insurance.

5.  Click Edit to the right of your Mortgage Lender.

Once you click Start or Update to the right of Mortgage Interest, Refinancing, or Insurance, you'll see the Delete button to the right.  Click that, and then you'll be able to re-enter your interest.