We all start off life in a position of being alienated from God by reason of the wrongs we have done in life. The bible calls these wrongs “sins”.
Unfortunately we cannot undo or repair these wrongs by our own efforts. No amount of good works can undo a wrong and so that is why we need a saviour and that is Jesus Christ.
When we come to Jesus in prayer (thats just speaking to him), and ask Jesus to forgive us, he looks at our heart and if we are sincere Jesus will enter our spiritual hearts through the power and work of God the Holy Spirit and begin renewing us from within.