For Search engine optimization creating a google xml-site map is most important. Google XML-Sitemap generate a special XML sitemap. This sitemap helps search engines like Google, Bing, Yahoo and Ask to index blog or website.
Google XML-Sitemap for wordpress:
Normally webmaster create Google XML-Sitemap manually. But if you are a wordpress user, then you can create your XML-sitemap just installing a plugin named Google XML Sitemaps which you can download from wordpress for free. This plugin supports all kinds of WordPress pages. It’s also supports custom urls.
Setting Google XML-Sitemap generator for wordpress:
Follow the steps to install this plugin in your wordpress blog.
1) Install Google XML-Sitemap . For more info see ().
2) Go to XML-sitemap from setting in wordpress dashboard.

3) If its first time that you are installing Google XML-site map than you will get a notice “The sitemap wasn’t built yet. ” Clicks the link (same as below picture)

Basic Option:
Your blog will be automatically notified in google, bing and ask.com. For yahoo you need to join yahoo developer’s network as a webmaster. clicks here to join Yahoo developers network.
Additional Pages:
No need to change any setting.
Post Priority:
There has three options. You can choose any one.
2)
3)
I choose 1st one cause i think all post are important for better index.
Location of your sitemap file:
Choose Automatic detection. So your XML-sitemap url will be www.yourdomain.com/sitemap.xml
Excluded items:
You can excluded categories and post through clicks the box.
Nothing need to change. After completing everything clicks on Update options.
How to configure Google XML-Sitemap WordPress plugin