"My dad is here."
Translation:Mój tata tu jest.
If one want's to generally negate the fact of being we use „nie ma”. So „jestem” - I am. „nie ma mnie” - both express both senses: „I am not present”, „I don't exist”.
We use „nie jest” when we want to negate some feature or some fact.
„On jest przystojny” - „On nie jest przystojny”.
„On tu nie jest szefem” - He is not a boss here.
"Mój tata tu jest" is the best answer, I'd say.
"Mój tata tutaj jest", although theoretically almost identical, somehow seems to me to give more emphasis, as if you corrected someone and said "But actually my dad IS here". Although... well, I guess then you'd have to emphasize 'jest' with your voice.
"Mój tata jest [tu/tutaj]" gives an emphasis on 'here', as if you were pointing somewhere. Generally we don't love such answers, putting such words at the end. If you really need to do it, at least use "tutaj", it's more emphatic.