Most Russian surnames end in ов for men and ова for women. Their Patronymic middle names also change depending on sex.

So a man named Ivan whose father’s name was Nikolai and surname is Fedotov would be:

Ivan Nikolaevich Fedotov (Иван Николаевич Федотов)

While his sister, Irina, would be:

Irina Nikolaevna Fedotova (Ирина Николаевна Федотова)

If you wanted to talk about their family as a whole their surname would become plural with a y at the end.

Fedotovy (Федотовы)