I am going out of country for 3 months is it okay if i leave the bike unused for 3 months ? and what to do to protect my bike for any loss ?
Disconnecting the battery is a good idea, specially if you have an alarm on it, to avoid it being discharged.
Besides that I'd leave the gas tank full (or close to full) so the water condensation inside the tank is minimal. Also, check the bike's manual to see the engine oil expiration (mine is 4000km or 6 months, whichever comes first) so you know if you'll have expired oil once you're back.
3 months is probably enough time for the engine head oil to be drained to the crankcase, leaving the cylinder unlubricated. So before the first start you might have to add some lubricant oil through the spark plug hole and start the engine without it for a while, so the cylinder walls get lubricated. This last step could be avoided if you had someone to start the engine at least once a month.
 Though it's what the manual says, I never met someone who waited that long to replace the oil, some go as far as changing it with 1000km. I try to stay in the middle ground and change it with 2000km checking the level and apparent quality of the oil (viscosity and color).
 As @Solar Mike pointed out in the comments, the oil expiration based on time is actually at the very least debatable. This question talks further on the matter, pointing reasons why this kind of recommendation does not have technical motivation. I'm still leaving it in the answer as it's recommended on some proprietary manuals, but adding the observation that you can choose not to follow it incontestably.