Recently I changed engine oil for my motorcycle. The oil filter was not in the service station so I am running it with the old one itself. If I want to change the oil filter is it required to drain the entire oil from the engine or can I just replace it without removing oil.
Replacing the filter without draining the oil is almost guaranteed to be very, very messy no matter where the filter's placed. You can re-use the oil as it's fresh, just drain it into a clean container, replace the filter and pour it back in.
That depends on where the filter is, if all the oil drains out when you remove the filter then add new oil , if not then you need to top-up by the amount lost in the filter.
If you specify make, year, model and engine you might get a more precise answer.