Suppose @indrajeet you have signup your password to GO, if any member of GO want to see your password this is becoz your password is store in GO database. for this purpose mainly hash is used. Your password will be combine with the function which will be in the hash form so that no anyone can decrypt it.
Next time again when you try to logged in , by putting your own username and password again it will be combine with the same hash function which will be in the form of hash output.This hash will try to match with the hash which is previously stored in the GO server. If both hash output are matching then only you can log in. and owner of GO who has the server he cant do anything with ur password. if they try to see your password they will get garbage value.