—>Altogether is an adverb (word describing a verb) meaning ‘completely,’ ‘entirely,’ ‘totally,’ ‘in total,’ or ‘on the whole.’
Examples: Altogether, it was a wonderful event. With his ex wives and fiance, he had five kids altogether. I stopped going there altogether after two bad experiences.
—>‘All together’ is a phrase meaning ‘gathered’ or ‘all in one place.’
Examples: We were all together for the first time in years. All together, the misfits would change the world.