You cannot enter an amount directly on Lines 18 - 20 on the Form 5695 in Forms mode.  You must enter your costs for the insulation, doors or windows in the TurboTax interview using Step-by-Step.

To enter Home Energy Credits -

Click on Federal Taxes (Personal using Home and Business)
Click on Deductions and Credit
Click on I'll choose what I work on (if shown)
Under Your Home
On Home Energy Credits, click the start or update button

That's the problem, TT does not have that option.  It keeps giving me error:

Form 5695 : A - Windows and skylights is selected but no entry present.

There is no way to correct error other than inputting directly on form 5695.

@DonC6306 What do you mean TurboTax does not have that option?

After selecting Home Energy Credits, you go through several screens asking about your home and what type of energy efficient product you purchased and installed on your home.

On the screen labeled  Tell us how much you paid for the energy-efficient improvements, you enter the amount paid for windows under the section Exterior windows (including skylights)

Right, it does ask me for information. When I get to the screen asking:

Improvements or replacements installed for enabling property.

It gives me the option for Windows and skylights, which is the only item that I have checked, because it does not give me an option for insulation (which is another energy credit), the program only gives me a place for entering information about panels, subpanels, branch circuits, or feeders. If I select continue, the program goes to the next screen asking about Condos and Co-Ops

@DonC6306 You wrote Improvements or replacements installed for enabling property

I am not seeing any screens which state "enabling property".  Is the property your main home?  Do you share the home with someone else?

Yes, and Yes.

It is about 3 screens past where it asks:

Enter your qualified energy property costs.

Next screen is:

Did you install improvements or replacements for enabling property?

If you select "YES", the next screen it takes you to is:

Improvements or replacements installed for enabling property

Which has the questions about windows and skylights, but no place to input the information.

"Enabling property" refers to upgrades—specifically panelboards, sub-panelboards, branch circuits, or feeders—that are installed in conjunction with qualified energy-efficient improvements to meet National Electrical Code standards.

If you only installed windows, there is no enabling property.  Did you enter an amount somewhere else on the form for heat pumps, biomass stoves, central air conditioners, etc.?

If not, then for this issue it would be best if you deleted the Form 5695 and then re-enter.