"Melanie starts school tomorrow."
"Melanie will start school from tomorrow".
1st sentence is simple present tense and the 2nd one is simple future tense, so my question instead of simple present tense can we use simple future tense?
Melanie starts school tomorrow.
Melanie will start school tomorrow.
are both correct. However, it is very common using present to express future, so your first example is the more acceptable.
However, there is another problem I want to emphasize:
Melanie will start school from tomorrow.
is incorrect, because there is no match between start and from tomorrow:
So if you remove "from", you get a correct sentence again.