By default when you create a new blog and hasn't applied the settings in the menus on the Dashboard Blogger Settings page, you won't find the search Description menu in the Post Entry Settings panel. Whereas the feature is quite important to complement the short description of each post that will be created later that will be displayed in the search results of Google searching.
To activate the menu can be done via settings menu their settings. Please choose the search prix fixe menu, then on the Search Preferences page, select the Meta Tag description click Edit and select Yes and save.
Leave the Description field in the Search Preferences menu empty, as we only need and use it specifically for the description of each post published, if the Description field is populated later when creating the post as well Filling out the search description will result in Duplicate Meta description, of course, this is not good for the health of your blog.
For those of you who have problems duplicat meta description on old posts that have been published please see the tutorial How to solve the problem Duplicat Meta Description Blogger.
So a quick Tutorial on how to enable the search description Menu on the Blogger Post entry page, hopefully, useful for those of you who need this Tutorial. See Also 3 Important things to note for beginner bloggers when creating new post entries before they're published.