Is it permissible to copy school assignments from friends, given that the studies are in a government school that teaches incorrect matters, and despite not wishing to study in government institutions due to their un-Islamic society?

It is not permissible to copy school assignments from colleagues because it is a form of cheating, which the Prophet, peace and blessings be upon him, forbade when he said: "Whoever cheats us is not of us." This also leads to many harms. However, if a student looks at his colleague's solution, understands it, then closes the notebook and writes the solution himself, there is no harm in that.