When I needed to do my taxes the first year on the street, I called 211 and they directed me to VITA. They did my taxes for free that year. I did have to show up with proof of my social security number and a few other things.
Addendum:
I typically do my taxes online. This has been a godsend while homeless in that I don't need to keep track of actual physical papers. I can access some of my old tax forms in PDF form and that is how I showed proof of social security number for my sons for the purpose of filing taxes with the help of VITA one year. I have always paid money to file online, whereas what VITA does is free. Supposedly, some sites will allow you to file for free online if your income is low enough. So far, I have not used them.
Addendum:
I typically do my taxes online. This has been a godsend while homeless in that I don't need to keep track of actual physical papers. I can access some of my old tax forms in PDF form and that is how I showed proof of social security number for my sons for the purpose of filing taxes with the help of VITA one year. I have always paid money to file online, whereas what VITA does is free. Supposedly, some sites will allow you to file for free online if your income is low enough. So far, I have not used them.