Know how your OneDrive and SharePoint content sharing works for external users.
If you want to manage external sharing of your organization documents,
or you want to know how your administrator is manage to remove external user access on documents after certain number of days,
and you do not have access to SharePoint Admin Center
then this is a quick document for you, it basically contains screenshots of all relevant settings which are self explanatory.
To configure external sharing policies, go to SharePoint admin center > Policies > Sharing
Its self explanatory, you need to set vertical slider as per your requirement
Explore “More external sharing settings” for more settings