Maybe I can help.
I’m on a H1B currently starting the green card process.
I don’t have formal education, but have been working as a developer for the past 16 years (13 at the time of the VISA application).
If you don’t have a degree, you can make it do with 3 years worth of experience for each year in college you don’t have. In my case, 12 years.
The experience is proved by employer letters and an “equivalence analysis” made by any college in the US where they write a piece of paper saying you have the equivalent knowledge of someone with a bachelors degree.
The challenge, really, for the H1B is the 85k cap (65k if you don’t have an advanced degree) and the application window which closes at April 7th.
Once your application is submitted you need to win the lottery (there are usually around 280k applicants) and wait for the VISA to be processed.
Potential employers are usually discouraged because they have to apply for you in April and you can only start working (if you are lucky) after October.
Let me know if you have any other questions.