I would like to make now (i.e. before April 15, 2019) 2018 contributions to my HSA and IRA. How should I report these in TT for my 2018 Taxes?

[Critter]

The same way you would have if you had made the contributions back in December ...

Where do I enter my HSA contribution?

Where do I enter my HSA contribution?

Where do I enter my HSA contribution?

In most cases, your HSA contribution is reported in Box 12 of your W-2 with the code W (Employer Contributions to Health Savings Account).

Tip: Code W actually reports the combined contribution – yours plus your employer's. So if you contributed $1,500 to your HSA and your employer matched it dollar for dollar, Box 12 on your W-2 would show $3,000 with a code W.

But what if I made an HSA contribution that wasn't reported on my W-2?

We'll ask about this uncommon situation when you step through the Medical section. Look for the questions Were HSA contributions made in 2018? or Do you need to make any adjustments to your HSA contribution amount? When you answer Yes, we'll open a screen where you can enter your contribution.

IRA's entered here : 

Federal Taxes Tab 

Deductions & Credits

-Scroll down to:

-Retirement and Investment

   -Traditional and Roth IRA contributions