I want to enable retention label that applies to all the files in a SharePoint Online site

[withviyaa]

I have a SharePoint Online tenant I want to setup a retention label that applies to all the files in a SharePoint Online site. Can anyone help ? 

[#2]

If you want to cover everything in a specific site(s), best use a retention policy instead of labels. https://docs.microsoft.com/en-us/microsoft-365/compliance/create-retention-policies?view=o365-worldw...

[#3]

Thanks Vasil. But my requirement is to enable retention label for the content in all the SharePoint sites in my tenant. any idea how to proceed?