I have bought a High capacity battery for Note 4. What I want to know is How long should I charge it for Initial time. And will there be any issues of using it ?
You're in a Windows forum! Android Central would be the better choice if you have more questions.
but we all deal with batteries regardless of platform. Personally I'd charge it until it is 100% full.
and we can't say if there will be issues or not, since it depends on the quality, luck, etc.
I'd keep usage to a minimum charging for the first time at least, but that's just me.
Modern phones are smart about not overcharging. You will find lots of people that warn you to pull it off the charger when it hits 100%, but they are reading from a very old playbook. Just put it on the charger and forget it. The important thing is not to drive it down to zero... that is bad for the battery. Charge it before it runs dry, and keep it as fully charged as is practical.