The balanced equation is:
Sulfuric acid is diprotic so is able to give up 2 H+ ions.
You are dealing with a reaction between a strong acid and a weak base, which results in the formation of salt and water. The reaction's general equation is
The complete ionic equation looks like this
The net ionic equation you'll often see is
However, sulfuric acid, which is a strong acid, reacts with ammonium hydroxide, which is a weak base, to produce salt, ammonium sulfate, and water.
Since it is a weak base, ammonium hydroxide will dissociate only slightly in water, so another version of the net ionic equation could be:
However, this does not change the balanced general reaction, which still stands as it was written in the beginning of the post.
You see that at the right of the equation there are 2
To even this out you may only double the whole
which works out right, because then the 2
to form 2
In reality it all happens a bit differently, with ions and stuff like that, but for balancing the equation this is enough.