What is the chemical equation?

Firstly a blue precipitate of copper(II) hydroxide is formed.
2NH3(aq) + 2H2O(l) + CuSO4(aq) → (NH4)2SO4(aq) + Cu(OH)2(s)
It is NOT advisable to write 2NH3(aq) + 2H2O(l) as 2NH4OH(aq), because NH4OH does NOT exist.

When an excess of ammonia is added, the blue precipitate dissolves and gives a deep blue solution of tetraamminecopper(II) hydroxide.
Cu(OH)2(s) + 4NH3(aq) → [Cu(NH3)4](OH)2(aq)