So, I know there is a way to share 'regular' folders and files with external users without sign-in. 

Is there a way to do this with sites? 
For example, I have a site: <https://mycompany.sharepoint.com/sites/NameOfSite>
and on that site I have folders and files: <https://mycompany.sharepoint.com/sites/NameOfSite/Documents/Folder/SubFolder/file.pdf>

Is there a way I can allow everyone with the above link to access 'file.pdf' without having to sign in?

Thank you.