They are articles which can be used as your own. Since most plr articles have been used repeatedly by numerous other sites, I'd suggest rewriting them to make them original.
i would suggest to use the original articles, one link from original content is 10 times better than the other links technique Thanks
PLR means 'private label rights'. You can reuse it according to the terms you bought it under (usually fairly lax). If you want to submit it to an article directory, you'll need to SERIOUSLY change it. Wrangle it, in fact, or it won't get published.
Ezine articles have to be unique, so PLR wont get accepted since someone else has already used it on the internet.