When a website first goes live or if there are a lot of changes to the site structure in terms of new content added or change of the URL / internal link structure then it may be time to submit a sitemap to Google.

The sitemap required to submit to Google needs to be in an .XML format and there are many ways to create one. Some sites offer free tools to allow you to make a sitemap but sometimes they are limited to a number of pages, so be wary about using these for larger sites.

Within a site map you can also tell Google how often it is expected to be changed and also the priority. The priority is normally set highest for your home page and then goes down as you dig further in to the site.

Once this sitemap has been created you can upload it to the main directory of your website and then submit the url to the sitemap to Google through the Webmasters tool web admin panel.