Why is TT calculating in a late fee on my Federal tax return? will that amount be on the coupon ?

You mean on 1040 line 38?  That is not a late fee.   It doesn't have to do with last year's tax return or not paying estimates for this year.  The penalty is an "estimated" amount.    It's a penalty if you owe too much or for not paying in enough withholding during the year or not paying in evenly.  It's very common and normal and expected for the IRS or state to bill you for more or send you a refund.

You might be able to eliminate it or at least reduce it.  You can go to Federal Taxes tab or Personal tab, under Other Tax Situations and select Start by the Underpayment Penalties. You will answer a series of questions that may reduce or eliminate the penalty. Or you can elect to have the IRS figure the penalty for you.  It's form 2210.

It's under

Federal or Personal (for Home & Business Desktop)

Other Tax Situations

Additional Tax Payments

Underpayment Penalties - Click the Start or update button

Yes it will be included on the 1040-V form used to mail your payment to the IRS.  The late fee is likely an underpayment penalty and interest.

The tax system is considered 'pay as you go' which means when tax is owed they want the money.  You don't necessarily have to send the estimated tax quarterly, however any underpayment can produce interest and penalty for late payment.

Reasons for penalties on a federal tax return:

1. Income where no federal withholding was paid in for you such as interest, dividends, sales of stock or property, etc.
2. Federal withholding was taken and paid from wages, however it may not have been enough