If you are younger than full retirement age and earn more than the yearly earnings limit, the amount you receive may be reduced.
If you are under full retirement age for the entire year, $1 is deducted from your benefit payments for every $2 you earn above the annual limit. For 2020, that limit is $18,240.
In the year you reach full retirement age, deducted is $1 in benefits for every $3 you earn above a different limit. In 2020, this limit on your earnings is $48,600. Social Security only counts your earnings up to the month before you reach your full retirement age, not your earnings for the entire year.
It is a good idea to check your earnings record at www.ssa.gov. Set up an account (easy to do).
I looked at mine. Two years were missing. Fortunately I had tax returns and W2s from those years. Social Security updated my earnings record very quickly.