Create an Office 365 plan for SharePoint Online. The Office 365 plan specifies which sites are backed up, how long the data is retained, and which sites are content indexed.
You will assign the Office 365 plan to the sites that you add to the SharePoint Online app.
If some sites have different backup requirements, you can create additional Office 365 plans for SharePoint Online.
From the navigation pane, go to Manage > Plans.
The Plans page appears.
In the upper-right area of the page, click Create plan, and then select Office 365.
The Create Office 365 plan dialog box appears.
In the Plan name box, enter a name for the plan.
Under Retention settings, specify how long to retain the data:
To retain for an unlimited time, select Retain indefinitely.
To retain for a limited time, select Retain deleted items for, and then specify the amount of time.
Search settings for Office 365 plans apply only to Exchange.