Search Center settings
As a SharePoint Online administrator, you can specify where searches should go by specifying the URL of your Search Center. For example, if you have created an Enterprise Search Center where users can search everything in your company, you can enter the URL of that site here.
Enter the address of your Search Center
Sign in to Office 365 as a global admin or SharePoint admin.
Select the app launcher icon in the upper-left and choose Admin to open the Office 365 admin center. (If you don't see the Admin tile, you don't have Office 365 administrator permissions in your organization.)
In the left pane, choose Admin centers > SharePoint.
On the search administration page, choose Search Center Settings.
In the Search Center URL box, type the URL of the Search Center site.
- Click OK.
It may take up to 30 minutes before changes take effect.