A casual conditional phrase meaning "if it's all right" or "if you don't mind," used to ask permission or propose something.
よければ、明日一緒に映画を見に行きませんか。
If it's alright with you, shall we go see a movie together tomorrow?
もしよければ住所を教えてください。
If you don't mind, please tell me your address.
よければ遠慮なく言ってください。
If it's okay with you, please don't hesitate to say so.