Business Page and Fan Page mean the same thing. Facebook used always to call them Fan Pages but recently (2018/19) started referring to them as business pages.

First up, you need a personal Facebook (FB) page. This will contain all your personal details and is verified by FB. You can use it for connecting with friends and posting personal stuff. But you don’t have to. You can create it and do nothing with it.

Business Pages are created from your personal FB page. Because your personal page has already been verified, they are easy to create.

Your personal friends will not automatically see your business page. Only those you specifically invite will see the page. To all intents and purposes, it is totally independent of your personal page. As the administrator, you are the only one who can swap between pages.

You can have more than one business page. Typically, you will have one for each on-line business you run.