Can you please explain Qaza Namaz? And when it can be read. For example today I missed asr, magrib and Isha so when would I be able to make them up?
You should make them up as soon as you are able, and perform them in the order they would have been performed normally (asr, then maghrib, then isha). The majority opinion is that it is obligatory to pray missed prayers in order, while Imam al-Shafi`ee considers it recommended.
Imam Malik and Abu Hanifah are of the opinion that if more than five prayers are missed, then it is not necessary to pray them in order.