It depends on how small it is coz there is no ideal size for a penis. If it is small but still enough to satisfy your partner during sexual intercourse (which one finds by asking the partner directly not just by assuming) then you penis size is absolutely normal and you do not need to do anything. Coz there is high likelihood of harm than benefit if you unnecessarily opt for penis enlargement surgery as there are no medical ways to increase length or girth of a penis.
Regards
Next Steps
Introspect and discuss with partner if the size is appropriate
Health Tips
Do not get in to trap of quacks, the right expert to consult in this context is a urologist.