Accha？namaste？What does these two words mean?

“Accha, Mr. and Mrs. Thakkar, namaste.” The man wearing a yellowed short sleeve dress shirt and a short necktie bows slightly to them. “Please, be comfortable.” He gestures to two chairs across from the desk.

Namaste (Devanagari: नमस्ते; formal: Namaskar) is a common spoken greeting or salutation originating from India. It is a customary greeting when individuals meet, and a salutation upon their parting. Younger persons usually initiate the exchange with their elders. Initiating the exchange is seen as a sign of respect in other hierarchical settings. It is the common greeting in Nepal as well.
When spoken to another person, it is commonly accompanied by a slight bow made with hands pressed together, palms touching and fingers pointed upwards, in front of the chest. This gesture, called Añjali Mudrā (or Pranamasana), can also be performed wordlessly and carries the same meaning.

Acha is a HINDI word for OK.