At it's heart, prayer is about conversation with God. Sometimes when we talk to friends, we have very long, in-depth discussions. Sometimes we have the simplest and shortest of chats. So it is in our relationship with God. Prayer can be just a few sentences to God, or even just a few words.
When Stephen, one of the early disciples of Christ, was martyred for his faith, the bible records him uttering just five words: "Lord Jesus, receive my spirit!"
Indeed, Christ was critical of those that seek to over-complicate what it means to pray:-
“The world is full of so-called prayer warriors who are prayer-ignorant. They’re full of formulas and programs and advice, peddling techniques for getting what you want from God. Don’t fall for that nonsense. This is your Father you are dealing with, and he knows better than you what you need. With a God like this loving you, you can pray very simply."
(Matthew 6:7-8, The Message)