You are being charged the penalty because you did not have enough tax deducted from your pay during the year. If you owed $1,000 or more when you filed your 2019 tax return, your total tax withheld for the year should have been at least 90% of the total tax on your return, or 100% of the tax on your 2018 tax return (110% if your 2018 AGI was over $150,000). If your withholding did not meet one of those requirements, you should have made up the difference by making quarterly estimated tax payments.
You can use the Tax Withholding Estimator on the IRS web site to make sure you are having enough tax withheld for 2020 and adjust your W-4 if necessary.
