If you are a U.S. citizen who is planning on acting as a green card sponsor for a family member, don't expect the process to be completed overnight. Various factors can stretch the process into months or years, depending on:
Both you, as the petitioner/sponsor, and the immigrant, will have to assemble a number of documents and fill out a number of forms. For starters, you will need to fill out Form I-130, issued by U.S. Citizenship and Immigration Services (USCIS), and attach to it proof of your U.S. citizenship as well as proof of your relationship to your family member (called the "beneficiary") in this process. USCIS must first process this petition, which can take several months.
In addition (usually later), you will need to prepare an Affidavit of Support on Form I-864, together with documents proving that you are able and willing to support the immigrant at an amount that is at least 125% of the U.S. Poverty Guidelines.
In addition, your family member will need to prepare various documents as his or her own application for a green card. The exact forms and process depend on whether your relative will be adjusting status in the U.S. or going through consular processing from another country.
Your relative will also need to undergo a medical exam, and get the doctor's report to submit with the green card application.
All of this takes time. You will need to coordinate with your family member to get information for some of the forms that you will be filling out, possibly contact government agencies for the official versions of birth and marriage certificates, contact the IRS for a certified copy of your tax returns, and so on.
When you act as a green card sponsor, the nature of your relationship with the person you are sponsoring is key.
If you are that person's “immediate relative,” then visas are immediately available, with no annual limit. Immediate relatives include the spouse (same-sex or opposite-sex), unmarried child under 21, or parent of a U.S. citizen.
If you are that person's “preference relative” -- meaning that you are a U.S. citizen and he or she is your child over 21, married child, or sibling -- then visas are limited by year, and long waits always exist in each category. When you file the I-130, the date USCIS receives it becomes your family member's "priority date" -- that is, a place on the waiting list. Only after your relative's priority date is "current" will he or she be able to submit the green card application. For more on this, see How to Determine Your Priority Date. That can take, on average, from 10 to 24 years, depending on category. (Brothers and sisters of U.S. citizens wait the longest.)
At every step of the way, you will be dealing with a government agency that is backlogged with other applicants. Every step of the process can take weeks or months -- even worse if you submit an incomplete application and the agency has to come back to you with a request for follow-up, or if you ask for a rescheduled interview. The typical processing steps you'll encounter include:
These waits are inevitably frustrating for the sponsor and the family member. You will probably wonder at some point along the way whether something has gone wrong. The trouble is, something might -- the immigration authorities are notorious for losing track of applications. Keep a close eye on their predictions for how long processing is currently taking, or hire an immigration attorney if you would rather turn this task over to a professional.