Samepage allows you to share either a whole folder or a single document. Sharing a document is perfect when you want to share single document from your otherwise private space to somebody else. They will receive write access to this document. Here’s a link to the help article about Understanding Sharing in Samepage.
You can share a Document with someone outside of your organization, or with someone inside the organization that does not already have access rights to the Folder where the Document resides.
To share a Document, open the Document, click on the gear icon at the top right corner and choose “Share”. Click the blue “Share with” link, enter the person’s name or email address and select to invite them as a guest to the page. Then click Close.
Public sharing is available just for the Page document.
It allows you to make content of the page public and accessible through the link. Only the page itself is visible online, the chat and the left panel are not.
To share a Document with the public, open the Document, click on the gear icon at the top right corner and choose “Share”. Click to turn on the “Public sharing via link” and then share the link with others. Click Close to close the sharing dialog.