Inbox - two columns

there are two columns in my inbox - one that says primary and other - how do i get rid of this?

Those are the new V10 Category Tabs where “alot of people want emails separated into various category sections” rather than all together in the One Inbox.

If you don’t want any Categories, “Right click in a blank area next to a Category” and deselect whatever you don’t want in the Category Tab on the menu.

You can also hide the Categories bar if you choose as well.