Jesus gave His followers words to pray: “This, then, is how you should pray: “ ‘Our Father in heaven, hallowed be your name, your kingdom come, your will be done, on earth as it is in heaven. Give us today our daily bread. And forgive us our debts, as we also have forgiven our debtors. and lead us not into temptation, but deliver us from the evil one (NIV).

Notice these are simple and direct words. Praying to God should be from the heart. Other instructions from the bible give specific words also that the worshipper can use in prayer. In the book of Joel, God calls the nation to return to Him giving them the words to say: Let the priests, who minister before the Lord, weep between the portico and the altar. Let them say, “Spare your people, Lord. Do not make your inheritance an object of scorn, a byword among the nations. Why should they say among the peoples, ‘Where is their God?’ ” (Joel 2.17 NIV).

Again, in Hosea the text records specific words to say that people could speak without first wondering what words to compose. They needed help and God even gives them the words to say if they were heartfelt: Take words with you and return to the LORD. Say to him: “Forgive all our sins and receive us graciously, that we may offer the fruit of our lips (Hos. 14.2 NIV).

The link above gives some prayers from Christian history.