When a customer enters, you may say 'irasshaimase.'
Welcome
You can say le-le or liyo.https://www.livinglanguage.com/community/discussion/315/saying-youre-welcome-in-japanese-not-recommended
"Irasshaimase." "Youkoso."
You may say 'youkoso.'
Bienvidos a mi restaurante.
シチュー You're welcome.
'Guamu e youkoso.'
kyoukai e yokoso
What they are saying is 'irasshai' or 'irasshaimase,' both of which can generally be translated as "Welcome!"
'Welcome to school' would be学校へようこそ (gakkou e youkoso) in Japanese.
watashi no heya e youkoso
You may say 'resutoran.'