According to them:

"Facebook is making changes to help organizations like yours find new supporters and stay connected. We've developed a new Page template for nonprofits with buttons and tabs that we think will be successful for your page.

The template is designed to show your most important content and make it easier for people to take action, like create a fundraiser. The new template emphasizes tabs for photos, events and more.

There's nothing you need to do now. You'll see this change applied on June 20. You can always choose another template and make more changes later in Settings."