This guides explains the best way to keep your site (and all its pages) up to date with three major search engines: Google, Bing and Ask
Initially, you should submit your main URL to the search engines manually, you can do that here: Submitting Your Site to the Search Engines
Once you have submitted, go 
and download the Google XML Sitemap plugin
- In your WordPress backend/dashboard go to Plugins -> Add New
- Search the Google XML Sitemap Plugin, install it, activate it
- Head into the settings section of your WordPress backend
- Go to the XML Sitemap settings
- Generate your first sitemap (using the link in the settings section)
- Make sure that you have the options enables to send sitemap changes to Google, Bing and Ask