Can we publish the WordPress blog in steemit? If we can, tell the process and tell the benefit in it please?
If we have done it, then which tag will we have to put in it?
Yes you can. And the amazing thing is you'll be rewarded too if your posts are good enough

There is a wordpress plugin named steempress.io. It is a project intiated by @fredrikaa @howo for the users who has an ongoing wordpress blog. With steempress you'll be able to-

Automatic posting of articles to the Steem blockchain
• Conversion and cleaning of text to look good on different websites
• Automatic self-vote
• Add an original link to your blog
• Custom tags for each article
• Default tags if no tags are defined for an article.
• Optional posting
• Bulk posting
• Post scheduling
• Multiple steem account support
• Add (or not) the featured image on top of the steem post
• Category filtering
• Custom footer on steem

And the amazing thing is that you will earn steem through using steempress. they'll reward you generouslly if you post brings value.

To know more visit steempress on steemit-
I don't think we can, because the plagiarism bots can't tell if you are the original author or not. So it would be flagged. You can, however, make slight changes to the work since it's yours, reference the original post and quote the sections that are lifted exactly.