Should I start to buy OneCoin? I am a professional software engineer and freelancer. I have heard about Bitcoin (and recently OneCoin) a long time ago, but I was not interested to indulge in this business.

Now, a few days ago a friend of mine told me that he has started this business (one coin) and he is purchasing OneCoin and in next year he will be able to earn enough money while selling the coins he would have purchased. I don't know if this business is good for me or not.

Should I start to buy OneCoin, since I am new to this business?
No, it's a proved scam, and they use misleading promotion to associate it with Bitcoin. If you google them, you'll find out that they are accused of scamming and are under investigation by authorities. That project is not related to Bitcoin at all.