Underpayment penalties can really add up even if your income is fairly consistent.
TurboTax automatically calculates estimated tax payments based on your income and withholding when you prepare a return using a safe harbor of the "prior year". If you withholding was not enough to cover this minimum, you will see quarterly vouchers as part of your return (you will need to download a pdf copy of the return to see the vouchers themselves as they are not electronically filed with your return).
If you make these quarterly payments and have the same or higher withholding, then you will avoid the penalties.
Conversely, you can have your financial institution withhold funds from your investments which would then boost your overall withholding.
One thing to note, withholding from income items like bonuses, RSUs, etc, may not be substantial enough to cover those taxes. In that case, it's advisable to make a tax payment (estimated tax payment) on those amounts to avoid being hit with underpayment penalties.
The IRS also has a free tool that you can use to tweak your W-4 so that you reduce your risk of the under payment penalty: https://www.irs.gov/individuals/tax-withholding-estimator
