The immediate relative category has special immigration priority. The immigrants in this category do not have to wait in line for a visa number to become available for them to immigrate because there are an unlimited number of visas available to immediate relatives. This category includes:
Family preference base immigration has four categories, F1 through F4, and covers U.S. citizens and lawful permanent residents. Unlike immediate relative immigration where a visa is always immediately available, you have to wait with family preference base immigration. How long you have to wait depends on the category, and the relationship with U.S. citizen or lawful permanent resident.
The categories are as follows:
The way to keep track of how long you have to wait to use an approved immigrant visa petition in a preference category is to check the Visa Bulletin issued by the Department of State.