The Present Simple is the most basic tense in the English language. It is an interesting tense because it can be used to express the future. Generally, though, we use it to describe the present activities or to talk about routines or habits.The present tense is the base form of the verb: I work in London.
But the third person (she/he/it) adds an -s: She works in London. - See more at: https://learnenglish.britishcouncil.org/en/english-grammar/verbs/present-tense/present-simple#sthash.JCXmomIV.dpuf