I looked but couldnt find the answer. My question is how many days usually does it take to get an answer from PHD applications in UK?. It's not written any universities website. How many days you got an answer from your applications?

It takes several weeks or a few months. Each program/institution is different, some slower than others. Plus, there may be two round of admissions.

I was shortlisted for an interview after 2 months, while they sent me an offer 4 or 5 weeks after the interview.