"San" is a Japanese honorific title that is used after a person's name. It is similar to "Mr.", "Ms.", or "Mrs." in English.
For example, you would say:
* 田中さん (Tanaka-san), meaning "Mr./Ms. Tanaka"
* 佐藤さん (Satō-san), meaning "Mr./Ms. Satō"
The honorific "San" is always written separately from the name.