What is God's will?

The will of God is that which is described in the Holy Scriptures.
King David in one of the psalms closely related to fulfilling God's law with fulfilling the will of God.
In Psalm 40: 8 it says: "To do your will, my God, has pleased me, and your law is in the midst of my heart."
In the same way the apostle Paul relates the knowledge of the law as the knowledge of the will of God.
In Romans 2: 17-18 it says: "Behold, you have the nickname of a Jew, and lean on the law, and glory in God, and know his will, and instructed by the law approve the best."

Everything that happens in the world is within the will of God?

It is very necessary to discern in the Word of God, that there are facts that occur in the world that are not within the perfect will of God, but that the Lord allows it within his permissive will.
Therefore according to the Bible there is a perfect will of God and a permissive will of God.

• GOD'S PERFECT WILL
The one that develops according to his Word.
For example: It is the perfect will of God that no one be lost and that all come to the knowledge of Jesus Christ.
In John 3:16 it says: "For God so loved the world, that he gave his only Son Jesus Christ, so that everyone who believes in Him may not perish and have eternal life."

• GOD'S PERMISSIVE WILL
It is found in the events that occur daily in the entire world and although they go against what is stipulated by his Word, the Lord allows them to happen.
To the peoples of the earth, many times they are not interested in taking God into account in their actions and the Lord allows it. However, this will not always be so, but when the time stipulated by Him comes, judgment will come upon the land of sin.
Today, we see that violence, evil, iniquity increase day by day. Many inhabitants of the earth wonder why God supposedly does not do anything, expressing in this way a terrible ignorance of the Word of God. Our beloved God manifests his permissive will, not because he is a God tolerant to sin or looks with indifference as the human being is lost to hell; but because He has placed in the human being free will or power of choice. Although his perfect will is that no one be lost, there will be many who will reject the call to repentance and not want to receive in their hearts the Savior Jesus Christ to be saved.
In Psalm 2: 1-5 it says, "Why do people rebel, and peoples think empty things? The kings of the earth rise up, and the rulers take counsel together against the Lord and against his anointed, saying, Let us break their bands And let us cast away his cords: he that dwells in heaven shall laugh: the Lord shall mock them, and shall speak to them in his fury, and shall trouble them with his wrath.
In Romans 1: 22-23 it says: "Professing to be wise they became fools, and changed the glory of the incorruptible God into the likeness of the image of corruptible man, of birds, of four-footed animals, and of creeping things."