I admit, I never had to think about this issue until we did a few interviews with certain book authors who wanted to see our final work before they were published. There are multiple ways to solve that problem. You can give others accounts with proper access to your posts. Another way to do this is to send folks what you have written as a PDF or Word document. Public Post Preview makes the process much easier. It lets you give people you choose access to unpublished posts.
The plugin is very simple to use. Once you install it, you will have the option to enable Public Preview for your unpublished works. All you have to do is copy and share the link this plugin offers with whomever you would like to see your posts. The plugin automatically cerates a preview link with an expiring nonce.
As mentioned earlier, there are others to tackle this problem. But I like the approach this plugin takes. It certainly beats having to share login credentials with people you may not know too well.