There are two settings that apply to sharing links by default:

• Default link type:
• Direct: Specific people
• Internal: Only people in your organization
• Anonymous Access: Anyone with the link (default)
• Default link permission:
• View
• Edit (default)

These settings are only available on the classic SharePoint Admin center page. They can be reached by clicking on the Shorten links or change their default permission link under Other settings on the modern SharePoint Admin Center | Sharing page.