Eleanor Rigby picks up the rice in the church where a wedding has been

Lives in a dream

Waits at the window, wearing the face that she keeps in a jar by the door.

Who is it for?

Eleanor is lonely and picks up the rice they throw at weddings almost like she is trying to live through the couple's happiness and relationship because she doesn't have her own.

She figuratively "waits" wearing a face she puts on at the door. The face is really a happy persona she tries to show everyone so they don't see how lonely she is.

The song now asks who is it for meaning why does she bother acting happy when she has nobody to care about her either way.