What are Custom Robots Header Tags
These are all the header tags used in blogger and their usage/meaning is defined below.
all : There are no restrictions for indexing or serving. This is default for all pages
noindex : Do not show this page in search results and do not show a "Cached" link in search results.
nofollow : Do not follow the links on this page
none : Equivalent to noindex, nofollow
noarchive : Do not show a "Cached" link in search results.
nosnippet : Do not show a snippet in the search results for this page
noodp : Do not use metadata from the Open Directory project (DMOZ) for titles or snippets shown for this page.
notranslate : Do not offer translation of this page in other languages in search results.
noimageindex : Do not index images on this page.
unavailable_after : [RFC-850 date/time]: Do not show this page in search results after the specified date/time. The date/time must be specified in the RFC 850 format
Steps to Enable It
Step 1. Log in to your blogger account Dashboard and click on your blog.
Step 2. Go to Settings >> Search Preferences.
Step 3. Click on edit link in front of Custom Robots Header Tags and then click on Yes option.
Step 4. Once you click on the Yes you will see many options. Simply tick on the options as shown in the below image.