How To Use Custom Robots.txt , Custom robots header tags in blogger Search preferences setting

You need to Use  this For better SEO and Traffic.

Step-1
Go to Settings --> Search Preferences and click Edit next to "Custom robots.txt."

select "yes".

Step-2
Copy and Paste this Text in to box same describe in picture.

User-agent: *

5	Disallow: /search

6

Allow: /

User-agent: *

5	Disallow: /search

6

Allow: /

User-agent: *
Disallow: /search
Allow: /

Sitemap: http://www.yourblogname.blogspot.com/atom.xml?redirect=false&start-index=1&max-results=500

Note: Please put your address : ), if you have custom domain like www.yourBlogname.com put it there.

step-3 Save changes.

For Custom robots header tags

Step-1
Click Edit and select yes.

Step-2
Please only check those boxes which are shown in picture.

Step-3
Save Changes.