Jesus is instructing His disciples on how to pray in Matthew 6.

After this manner therefore pray ye: Our Father which art in heaven, Hallowed be thy name. Thy Kingdom come. Thy will be done in earth, as it is in heaven.

What is God’s will?  Let’s consider the obvious from Scripture.

The Lord is not slack concerning his promise, as some men count slackness; but is long suffering to us-ward, not willing that any should perish, but that all should come to repentance. 2 Peter 3:9

If you are not a Christian, if you have not repented and trusted Christ, then you are not in God’s will.  What does it mean to repent?  To repent means to change one’s mind; to change one’s mind about your sin (sin separates one from God); to change one’s mind about who Jesus is (He is God); to change one’s mind about what He did for you (He died in your place); to believe in His death, burial and resurrection (not yourself or the church); to change one’s mind about trying to earn salvation (it is a gift); to change one’s mind about who to trust for salvation (trust Jesus Christ and His merit alone).  Changing one’s mind results in a change of direction.

For this is the will of God, even your sanctification, that ye should abstain (to keep oneself) from fornication* (illicit sexual intercourse, including adultery): That every one of you should know how to possess his vessel (exercise self-control) in sanctification (separation unto God through Christ as a result of obedience to His word) and honour (a valuing); Not in the lust (desire in an evil way) of concupiscence (to set one’s heart upon), even as the Gentiles which know not God: That no man go beyond and defraud his brother (stir up a desire in another that cannot be fulfilled biblically) in any matter: because that the Lord is the avenger of all such.                             I Thessalonians 4:3-6

In everything give thanks: for this is the will of God in Christ Jesus concerning you. I Thessalonians 5:18

Dearly beloved, I beseech you as strangers and pilgrims, abstain from fleshly lusts, which war against the soul; Having your conversation honest among the Gentiles: that, whereas they speak against you as evildoers, they may by your good works, which they shall behold, glorify God in the day of visitation.  Submit yourselves to every ordinance of man for the Lord’s sake: whether it be to the king, as supreme; Or unto governors, as unto them that are sent by him for the punishment of evildoers, and for the praise of them that do well.  For so is the will of God, that with well doing ye may put to silence the ignorance of foolish men: I Peter 2:11-15

I beseech you therefore, brethren, by the mercies of God, that ye present your bodies a living sacrifice, holy, acceptable unto God, which is your reasonable service.  And be not conformed to this world: but be ye transformed by the renewing of your mind, that ye may prove what is that good, and acceptable, and perfect, will of God.          Romans 12:1-2

Jesus speaking: For whosoever shall do the will of God, the same is my brother, and my sister, and mother. Mark 3:35

Note: When we pray the disciple’s prayer,…in earth as it is in heaven, we are asking for the salvation of the lost on earth (there are no unbelievers in heaven), we are asking for purity or the righteousness of Christ (nothing sinful or defiled shall enter heaven), and we are expressing thanksgiving for whatever happens on earth (there are no  ungrateful ones in heaven).

*Fornication as a general term includes all sexual immorality.

…let the word of Christ dwell in you richly…