Does lemon with hot water help in detox? if no, what should be taken for that purpose?

Not really: Humans, designed or evolved over millions of years, are self-cleaning. That means we should eat what we are designed to eat, and our bodies will clear out unneeded materials without help. No supplements are needed, unless one wants extra fiber to move the bowels better. Proper diet, enough exercise, and a healthy mind should normalize bowels. Diseases may need treatment, but not "cleansing/detox".