Line f4 is the amount borrowed in 2020.  This should be posted in step by step as a 2020 mortgage.

To post your mortgage interest you will start with:

• Deductions & Credits
• Select Mortgage Interest & Refinancing
• Enter Bank name ( you may import the file, or if you have a copy you may enter it yourself)
• To enter yourself select Change how I enter my form
• There are two boxes. Do not select either
• Select Type it myself
• Continue with the interview

did not answer my question, but I fixed it myself...thanks

What did you do to fix it?  I am having the same problem.

On the worksheet, I clicked the box where I needed to enter my amount.  Then I went to edit and I clicked override.  I was then able to type in the box.

THANK YOU. It's after 11 pm, I am 3 whiskeys in, and I really really wanted to finish my goddamn taxes. Turbotax needs to fix this glitch! 

In the interview you get to a page that asks - tell us how you've used this loan.  There are 3 questions, but no entry box for the question: What is the original balance?  By going into Forms, and right clicking (i have a PC) on the highlighted spot on F4 in the Home Mortgage Interest Limitation Smart Worksheet you can select Override, then you can enter the amount.  When you return to the interview, a box with the amount has magically appeared.

right click the box needed to be filled as explained by another previous and click on override and then enter the amount in the field required.

THANK YOU SO MUCH!  I was so frustrated by not being able to enter an amount in Line F4.  Your right click trick did the trick!  Whew!