What documents do I need to file when opening an ecommerce business in Massachusetts?

I have an ecommerce wholesale website that I just got up and running. I am looking for some information on the documents I need to become legal.

We are a wholesale reseller, we receive products from wholesalers and sell them for lower prices than our competitors.

I have applied for and have received my EIN. When searching online and looking for details on what kinds of documents I need to file, it is very confusing.

Do I need a business license? Reseller license? Vendor certificate? any other license/certificate?

also, what is the best bank to open a small business account with?

Can someone please tell me all the required documents I need to file for my wholesale distribution ecommerce site, and how to obtain them?

Greatly appreciated!!