After you file

See https://www.irs.gov/payments/underpayment-of-estimated-tax-by-individuals-penalty

We may reduce a penalty if any of the following apply:

• You or your spouse (if you file a joint return) retired in the past 2 years after reaching age 62 or became disabled and you had reasonable cause to underpay or pay your estimated tax late. See Waiver of Penalty in Instructions for Form 2210PDF.
• You had most of your income tax withheld early in the year instead of spreading it equally through the year. Complete Form 2210, Underpayment of Estimated Tax by Individuals, Estates, and TrustsPDF.
• Your income varies during the year.