If it is a customer, just add a CompanyName field to the Customer table.

Company info is much more complicated than individual persons' info.  In my old job, not only did each company have the basic contact info (name, address, phone, etc.), but also:

- Multiple ship-to locations, such as companies that own stores in several places.
- Multiple bill-to locations, because larger companies often have multiple invoicing departments.
- Multiple distribution centers, or "hubs" that distribute goods to other locations.

Different companies may also use different "payment terms."  One may use "Net 10 EOM" (payment due 10 days after end of month), and another may use "8/10 ROG" (8% discount if paid within 10 days after receipt of goods).  So your company need to store these for different companies.

It all depends on your business practices.  Some industries or businesses require more complicated info than in others.

Yep. It's all how you want to handle it. You can do one company with multiple people at that company (2 tables). You can just add a company name to the customer table (1 table). You can also make companies and people a single unit called an "entity" which is what I do in my ABCD. Then you can relate them all together with self-joins. All about how YOU want to put your Legos together.