Examples

1. Alien A is outside the U.S. Alien A is not eligible to apply for adjustment of status. A may only apply for consular processing.
2. Alien B is in the U.S. and is in a valid nonimmigrant status. After B's immigration petition is approved, B may apply for either consular processing or adjustment of status.
3. Alien C is in Texas. C's family-based immigration petition is approved and a visa number is available. Because the time frame for adjustment of status  based on a family-based immigration petition is long, C chooses to apply for consular processing for strategic reasons.
4. Alien D's National Interest Waiver petition is approved, but D's H-1B is going to expire. D may apply for either consular processing or adjustment of status. Because applying for adjustment of status has the benefit of a work permit, D chooses to apply for adjustment of status.