Salvation is a requirement to enter into Heaven. Salvation is for all who believe on Christ Jesus.
John 3:16-17 says: For God so loved the world that He gave His only begotten Son, that whoever believes in Him should not perish but have everlasting life. For God did not send His Son into the world to condemn the world, but that the world through Him might be saved.
Romans 10:9-10 says: That if thou shalt confess with thy mouth the Lord Jesus, and shalt believe in thine heart that God hath raised him from the dead, thou shalt be saved.For with the heart man believeth unto righteousness, and with the mouth confession is made unto salvation.
This is why we say the Sinner's Prayer. The following is an example of a Sinner's Prayer that is used by many, however, you may use your own.
The Sinner's Prayer
Lord Jesus, I come before you and confess that I am a sinner. Jesus, I believe that you died on the cross, and that Almighty God raised you from the dead. I pray that you forgive me of my sin, and be my Lord and Savior. In the name of Christ Jesus I pray this request. Amen.
After saying the Sinner's Prayer, and meaning it with your whole heart, you are made anew in the spirit and your sins are instantly forgiven, simply because you have confessed and asked for forgiveness. From that moment on, the more time that you spend with God, the closer God will be to you, and the more peace that you will feel. God enjoys hearing praise and loving words from His children, and there will always be more of Him around those people who worship and praise Him. God's presence will give you strength and peace. Just remember that the amount of God's presence in your life is directly proportional to the amount of time that you spend with Him, in prayer, in praise, and in worship of the Almighty God.