Didn’t file last year taxes

[Bruce901]

I made about 3500 self employed in the last quarter of the year of 2023. What should I do to not be penalized and pay those?

[DoninGA]

IRS Tax Topic for underpayment of estimated taxes - https://www.irs.gov/taxtopics/tc306

If you didn't pay enough tax throughout the year, either through withholding or by making estimated tax payments, you may have to pay a penalty for underpayment of estimated tax. Generally, most taxpayers will avoid this penalty if they either owe less than $1,000 in tax after subtracting their withholding and refundable credits, or if they paid withholding and estimated tax of at least 90% of the tax for the current year or 100% of the tax shown on the return for the prior year, whichever is smaller.

Since the Self-Employment tax on the $3,500 of SE income will be less than $1,000 you should not have an underpayment penalty, assuming that is your only income for tax year 2023.

[Opus 17]

Your estimated taxes for the last quarter of 2023 were due January 15, 2024.

If you are filing a late return now, there is nothing you can do before you file to reduce your penalties.  However, if Turbotax suggests paying a penalty, see if you can decline the calculation.  Just file and pay your taxes.  If the IRS sends a penalty assessment letter, you can apply for a one-time abatement/waiver for cause (such as, this was your first year and you didn't know the rules.)  It's pretty easy to get a waiver of the penalty if this is your first time.  However, you will also owe interest.  Interest can't be waived, but the interest on the late tax payment will be recalculated if the penalty portion is removed.