What to do when I didn't follow though to put money in my ROTH IRA account and now April 15th deadlline is passed?

If you said it was to a ROTH IRA nothing showed up on your tax return.  You don't get a deduction for a ROTH contribution.  There isn't anything to change on your return if you didn't make the Roth contribution.  Check if it showed up on Schedule 1 line 20 which goes to 1040 line 10.  That is only for Traditional IRA deductions.

First ... too late to make a contribution for 2023 now.

Next ... the contribution only affects the credit form 8880 so if you had nothing on that form there is nothing you need to do ... that information was not sent to the IRS.

Thank you!

Thanks! there is nothing on form 8888. The only thing on the IRA worksheet is that the basis for ROTH contribution is overstated by the amount that I did not really follow through to put into my ROTH IRA account.