Christians believe that God created everyone to be in relationship with him, and that he loves to hear from each one of us as often as possible. Just like you might talk to a close family member, so we have the privilege of talking to God. You don't even need to be a Christian. God has made himself known to many who have reached out to him with an open heart.¹

¹ https://christianity.org.uk/article/prayer

The Lord's Prayer is a great place to start, Matthew 6:9-13.

Jesus said, "this then is how you should pray:

Our Father in heaven, hallowed (holy) is your name,
Your kingdom come, your will be done
On earth as it is in heaven.
Give us today our daily bread.
Forgive us our debts (sins) as we forgive our debtors (those who have wronged us)
And lead us not into temptation, but deliver us from the evil one
(The following line is not in scripture, but it finishes the prayer nicely)

For thine is the Kingdom, the Power and the Glory, for ever and ever, Amen.