year-end tax adjustment; the procedure to reconcile over- or under-withheld income tax for the year (usually handled by an employer for employees).
会社は毎年年末調整を行い、過不足を精算する。
Companies perform year-end tax adjustments each year to settle any over- or under-withholding.
年末調整のために保険料控除の証明書を提出してください。
Please submit proof of insurance premium deductions for the year-end tax adjustment.
フリーランスは自分で確定申告をするため、年末調整は関係ない場合が多い。
Freelancers usually file their own tax returns, so year-end adjustment often doesn't apply to them.