This is a very common and polite welcome greeting used by staff in shops, restaurants, or hotels to customers. It means "Welcome" or "May I help you?" and is used to invite customers in and signal that service is available.

お(みせ)やレストランなどで、店員(てんいん)がお客(きゃく)さんを歓迎(かんげい)する時(とき)に使(つか)う丁寧(ていねい)な挨拶(あいさつ)です。「ようこそ」や「何(なに)かお手伝(てつだ)いしましょうか」という気持(きもち)ちです。