Where can I get the paperwork to start filing?

If he entered the US unlawfully, under the current immigration laws, even if he is married to a US citizen and financially the bread winner of the family he is not eligible to legalize his status within the US. Please let me know if you have any additional questions or how I can be of further assistance to you in this matter.

Assuming you refer to immigration matters, you will find virtually all applications and petitions for immigration related benefits on line at the USCIS.gov web site,

Your question is too vague, in order to receive an accurate answer we need more facts. For example what are you trying to do? Like petition for a relative, daca what type of application. Second each application has its own separate requirements and thus you have to see if you qualify for the benefit being sought. Each application has its own mailing address and it is usually based on the state you reside. If you know what type of application you are submitting read the instructions for the form. Furthermore, just because he is the provider it will not be enough for most applications. Hope this helps.

Well, I assume you are a US citizen and he is not. Depending on how he entered US and a lot of other things, a seasoned attorney can tell you when you may file so he can benefit from your filing. Please consult with an attorney in your area.