In layman language we can say that Put/ Call ratio (PCR) provides information about the ratio of trading volume of put to call options. Changes in this ratio are indicative of the prevailing market sentiment.
For instance, a higher PCR, which arises when put volumes are relatively higher than that of calls, signals a bearish sentiment. On the contrary, increase in volumes of call options, by the virtue of its definition, can largely be assumed as an indicator of a build up in bullish sentiment. You can get more input about Put call ratio affecting market here.
You can get to know all about F&O Tips here and also get all about Future and option basics here.