The Japanese particle e (へ) is used to show direction. E can only be used with verbs that have physical direction or a destination. It's always written using the hiragana character HE (へ), but it is pronounced E (え)
Ni is also used to show direction except it shows to a final destination. The particle e gives more of a sense that one is setting out towards a direction. It shows a general direction as to where someone is headed.
He went towards Bookstore = kare wa honya e itta
(She) wants to go outside = soto e ikitai (外へ行きたい)
Tomorrow, (I will) go to park = ashita, kouen e iku
It's also commonly used to welcome someone to a country or place.
Welcome to Japan = nihon e youkoso (日本へようこそ)
Welcome to Osaka = oosaka e youkoso (大阪へようこそ)
Welcome to our house = watashitachi no ie e youkoso