How can I add a statement/explanation for 1040, line 5a and 5b? There's no longer an "explain" button.

[DoninGA]

Why do you think you need to add a statement for Lines 5a and 5b on the Form 1040?

You only needed to enter the Form 1099-R to populate those lines.

If you need any type of exception to a penalty, that is entered on Form 5329 and you are give the option to enter that form in the Form 1099-R section after completing entry of the 1099-R.

[mccallbills]

Thanks for this response. I'm a retired minister so am permitted to deduct from line 5a an amount attributable to the costs of providing a home -- an archaic practice, but still a protected benefit. My pension board sends a 1099-R with a total and checks "taxable amount not determined." I enter that total amount on 5a, then enter an explanatory statement about deducting housing costs and the net amount on 5b. I'll be philosophical: either they accept it 'cause I've done this for 50 years, or they ask for clarification and I'll send it in. 

[MarilynG1]

If Box 2b is checked on your 1099-R it is appropriate to subtract your housing expenses from the amount in Box 1 and enter that amount in Box 2a (Taxable Amount).

Here's more info on Excluding Clergy Housing Costs.

@mccallbills