I have heard and also read in various threads that mining is too risky. The invested money can all be gone with a blink of eye. Actually i am not sure wither i should do it or not. If i invest, then is there any chance to loss all the money?
If i invest, then what should be the amount first?
And in which sites would be better to do mining?
Most of the cloud mining companies are scam. Some which aren't, it is never profitable to invest in them. You will just keep on waiting for your returns. With all that huge fees they will rob you of your money. Stay safe and instead buy some Bitcoin and hold. You will enjoy better ROI.