Everything you submit to USCIS must be translated to English. This includes Form I-485 and all evidence you provide to prove your eligibility.
Certified English translation is included with SimpleCitizen at no extra cost.
Start a green card application here.
Renew your green card here.
Apply for Citizenship here.
These guys are registered with the USCIS as accredited translators and help with translation of the supporting documents for the Form I-485. http://www.inwhatlanguage.com/
I have all my supporting documents ready to upload. Is the USCIS certified English translation something that SimpleCitizen takes care of? Or do I have to do this step on my own?
When using SimpleCitizen to prepare an application (green card, renewal, or citizenship), all supporting documents are automatically translated into English by a certified translator at no extra cost.
Here’s a great place to get started.
A couple more resources:
The Ultimate Guide on Getting a Green Card
How to Become a United States Citizen