New Blogger interface provide an facility to add meta description tag for each an every post.
First you enable your Meta description tag for your post. For that,
- Login to your blogger account.
- Go to Setting > Search preferences.
- Then click on Edit link in Meta tags > Description.
- Select "Yes" option and write description for your Homepage and click on save.
Now, you enabled description meta tag for all post in your blog.
- Finally when you create a new post or edit post, your able to add description meta tag in your post as display in below image,
