“My future husband and I want to get married. He’s already in the US but his tourist visa has expired and I have no idea what we need to do. I’m a US citizen and he is from the Dominican Republic.”
We get asked this question quite a bit and generally a foreign national is barred when adjusting status but there’s an exception. If you’re married to a U.S. citizen or they’re an immediate relative, the US Department of Homeland Security and Department of State generally waives that inadmissibility. You can then file for adjustment of status (AOS) but you should not leave the United States during this process. AOS means that you file Form I-485, have biometrics taken, and typically have an interview with a USCIS official.
This is assuming your fiancée is admissible, meaning they have nothing in their background that would prevent them from filing it or what caused them to get denied. That part of it is very important. If you feel that your fiancée is inadmissible, meaning they do have something in their background or they entered the US illegally, you may want to consult with an immigration attorney, just to be sure.
As long as you entered the United States legally and you are married to a US citizen, in most cases, you are eligible to adjust your status. That’s also known as applying for a green card. You would need to file your I-485 along with supporting documents.