Drive is where you can collect and organize everything you made, ranging from scrapbooks, storyboards, reference pictures and other materials, to plots, , brainstorming materials, drafts and finalized manuscripts.
From here you can grant access to people to read something if you gave them a link for a specific file, or to edit the file
When you view the contents of your drive, you can right click on any file and pick "Share" which allows you to customize specific sharing options.
Sharing via link allows anyone to pass on the link and with that view or edit the document you shared. It can be ideal for posting the link somewhere to grant readers access to your works.
Alternatively you can directly invite people by email address which allows you to limit accessibility to specific people.
Clicking the "Change..." button allows you to further specify settings where you can make something public access without the need to sign in to a google account.