Please suggest some free auto bookmarking software or a WordPress plugin.
how to automatically add bookmarks while someone enter my blog.
are you asking for a way to force a bookmark into the browser of someone visiting that blog or website?
Have you tried the Onlywire plugin? Here's an article I found online about it - I used to use it, though I haven't used it in a while, I'll likely go back to using it myself. When I did use it, it worked very well:
Hope that helps you!