An import processing aspect to understand is whether your case will be filed as a consular processing or change of status petition. Consular processing refers to the step that requires a visa applicant to submit immigration forms to their home consulate or embassy, appear for a visa interview, and await a visa stamp in their passport. This process is required for almost all visa applications made while a person is located outside of the U.S.
On the other hand, the change of status process is a means by which a person already present in the U.S., on a valid non-immigrant visa, such as a B-2 visitor visa, can apply to change their visa status to another status. The key to a change of status petition is that the petition must be received by the United States Citizenship and Immigration Services (USCIS) prior to the expiration of the I-94 card issued to the applicant. As long as this is achieved, and as long as the current visa status the applicant is on allows for a change of status petition to be filed, as most do, the applicant may remain in the U.S. until a decision is rendered by USCIS.
Note that understanding the difference between a visa stamp in your passport and an I-94 document is of utmost importance and plays a critical role in whether one must consular process or if you have the option of filing your case as a change of status petition. Read more about this in our FAQ dedicated to this issue.