Immigration topics include US citizenship, visas, international adoptions and marriages, green cards and deportation. Immigrants, people seeking a permanent residence card or "green card," and non-immigrants, people seeking temporary entry to the US to work or visit temporarily with a visa. The main governing body, the USCIS, formerly the INS, also works with people looking for asylum, naturalization as well as immigration crimes, including illegal immigration.
Visa applications such as the H-1B are numerous and each one has special guidelines, extensions, and processes. Reading these articles and an experienced immigration lawyer can help with the details and help you understand the process and what you need to do.
In general:
For immigrants and nonimmigrants alike, the first step in coming to the US is obtaining a visa. Above, you learned the basics about visas - find out here which specific nonimmigrant visas are right for your need.