Answer:
Your question is very broad,
it could be taken as "How do you justify your faith?"
It could be asking how you justify on a document which i doubt
I am just going to assume you mean "How does one declare or make oneself righteous in the sight of God."
Now depending on what religion you follow the answer will be different
Most say you need to be baptised of some sort and declare your love to God or Jesus
and then be the best person you can for the rest of your life
Paul brought in the idea of justification by faith
meaning that all you have to do is believe to be saved
of course this can be seen in different lights
to be classified as believing do you just have to say you believe or do you have to follow all of the commandments that are in the bible?
People use Deuteronomy 11:1 "Love the LORD your God and keep his requirements, his decrees, his laws and his commands always." to prove that to obedience is needed to justify. And many other verses like Exodus 19:5