As a Global admin or SharePoint admin in Office 365, you can use the OneDrive admin center to control how sharing works at the organization level in OneDrive and SharePoint Online. Because each OneDrive is a site (previously called "site collection") within SharePoint, your organization's SharePoint settings and OneDrive settings are related. 

How To Change Share Link Settings 

1. Log in to your Office portal. 

2. Click on Admin app. 

3.  Click on Admin Centers, and then select OneDrive. 

4. Click on Sharing in the left navigation pane. 

5. There settings in the right panel are as shown. 

• Let Users share SharePoint content with external users: As the name suggests, this setting allows the users to share SharePoint content with external users. There are three settings in the dropdown in this setting- Only External Users (Sign-in required), New and Existing external users (Sign-in required) and Anyone including Anonymous Users. 

•  Let Users share OneDrive content with external users: As the name suggests, this setting allows the users to share OneDrive content with external users. There are three settings in the dropdown in this setting- Only External Users (Sign-in required), New and Existing external users (Sign-in required) and Anyone including Anonymous Users. 

• Default Sharing Links: This setting allows us to choose the kind of link that's selected by default when users share items. There are three options to choose from in this setting- Direct-only people who already have permission, Internal- Only People within your organization, Anonymous Access-Anyone with the link. 

• Anonymous access Links: There are three settings in this section. They are- Links must appear within this number of days (This value sets the expiration time for links. Entering a value of 0 will set it so that links do not expire), Files(It has a dropdown menu that allows us to set how much access the person to whom the link is shared have over the file , whether view ,view and edit or view, edit and upload)’ and ‘Folders(It has a dropdown menu that allows us to set how much access the person to whom the link is shared have over the folder , whether view ,view and edit or view, edit and upload)’. 

• Limit External Sharing by Domain: It contains only one option Allow or block sharing with people in selected domains. 

• What can External Users Do: It is a checklist containing two options- Let External Users share items they don’t own, and External Users must accept sharing invitations using the same account that the invitations were sent to’.  

6. After configuring these settings as per your need, click on Save. Your External Sharing settings are saved.