Keeping your content organized and guiding your visitors to the right page shouldn’t be a problem for smaller sites. Things are a bit more complicated if you run a large website with a ton of content pages. Adding an A-Z index page to your website is one way to better serve your visitors. A-Z Listing for WordPress can handle the job.
The plugin simply lets you create pages with letters and links under each. If there is no page associated with a given letter, the widget displays that letter unlinked. Once you have installed the plugin, you can create your index page by adding the appropriate function or shortcode.
You also get a widget to display your sitemap in your sidebar. The plugin is available for free.