The Book of Common Prayer says that prayer is "responding to God, by thought and by deeds, with or without words." With this form you are invited to put to words what is on your heart.
There is no single way to pray. Here are some "types" you might consider:

Petition: prayer acknowledging our own needs
Intercession: prayer that "brings before God the needs of others"
Thanksgiving: prayers that offers to God "all the blessings of this life, and for whatever draws us closer to God."

You can also just write the name of a person or group of people you are holding in your heart, and if you wish, a few words about why you are holding them in prayer.