Now a days we sometimes seeing the price of Bitcoin falling along with others also falling.
At that time if I have Bitcoin then what should I do ?
Should I sell or hold?
You should hold at this time. Hold it until the price rises, because we cant determine what will happen at the price. No one knows when it will rise so the best thing to do is to hold. Buy more coins and hold it, so in the future you are able earn your desired profit. You may regret it if you sell your bitcoin now.