Each sorority chapter has its own requirements, rule and regulations you will need to meet in order to join. In general, however, sororities expect a minimum high school or college GPA above 2.5. In addition, sororities expect your attendance at the college or university.
Recruiting events vary among colleges and universities or even with sororities; however, most institutions have at least one week-long event annually to facilitate the recruitment process. These recruiting events give you the opportunity to interact with the different sororities and learn more about them. In addition to the formal recruiting activities, some sororities also have informal recruiting events specifically aimed to increase membership in that sorority. In order to learn about those events, speak to those sororities directly.
Bidding processes vary among campuses. In general, however, you express your preference to join a sorority and if the sorority is interested, the organization sends you an invitation. In most cases you will likely receive more than one invitation, but every sorority will expect your loyalty, so you may only accept one invitation. It is important to choose wisely and accept an invitation to a sorority you feel most comfortable with on your own terms.
With any sorority, once you accept an invitation, whether through a formal or informal process, you are a new member, but not a full-fledged member. There is an "initiation" period, often lasting an entire semester when you will need to prove your worth to the sorority. This means you need to perform well academically; attend all events the sorority hold; learn the history, traditions, and values of your chosen sorority; and learn the operations of running the organization. Satisfactory performance during the initiation period culminates in an initiation ceremony where you are inducted into the sorority as a full-fledged member.