How can I hack others email id passwords and how can I see their webcams without them knowing because my friends come to know my passwords and hack my webcam

You will not get that answer here, what you want to do is illegal and we do not help anyone break the law. Most likely they got your password from you and you did not realise it.

Anyone giving information on this would have that info deleted and be banned from this site.

Illegal access to a private computer system is illegal under US law. WE do not support or condone illegal activities here.