This is a prayer that you can say, however it is just a sample. You may want to be more personal about it, there are no magic words that get you saved. Just have a conversation with Jesus. The important points are that you
Admit you're sins and acknowledge your sinful nature. Next repent of those sins, or that lifestyle, this means that not only are you sorry about them but you are going to turn away from sin and live a righteous life. Ask for forgiveness from Jesus, He will. Let Jesus know that you believe in his sacrifice on the cross for you and put your life in Gods control. Commit to living a Godly life walking in the love and belief in Jesus.
Here is the sample, you should personalize it and let go with a conversation with Christ.
I admit that I am a sinner. I have done many things that don’t please you. I have lived my life for myself only. I am sorry, and I repent I ask you to forgive me.
I believe that you died on the cross to save me. You did what I could not do for myself. I come to you now and ask you to take control of my life; I give it to you. From this day forward, help me to live every day for you and in a way that pleases you.
I love you, Lord, and I thank you that I will spend all eternity with you.
This sample prayer is from thoughtco.com