Hey hope this helps. So starting off with a few things that cause hormones.
The Endocrine System , So The best way to answer the question "what are hormones?" is to take a look at some of the major hormonal systems in the body. Hormones are created by glands, which are part of the endocrine system. The main hormone-producing glands I've listed below
Hypothalamus: The hypothalamus is responsible for body temperature, hunger, moods and the release of hormones from other glands; and also controls thirst, sleep and sex drive.
Parathyroid: This gland controls the amount of calcium in the body.
Thymus: This gland plays a role in the function of the adaptive immune system and the maturity of the thymus, and produces T-cells.
Pancreas: This gland produces the insulin that helps control blood sugar levels.
Thyroid: The thyroid produces hormones associated with calorie burning and heart rate.
Adrenal: Adrenal glands produce the hormones that control sex drive and cortisol, the stress hormone.
Pituitary: Considered the "master control gland," the pituitary gland controls other glands and makes the hormones that trigger growth.
Pineal: Also called the thalamus, this gland produces serotonin derivatives of melatonin, which affects sleep.
Ovaries: Only in women, the ovaries secrete estrogen, testosterone and progesterone, the female sex hormones.
Oh and by the way the person below me copied and pasted her answer here's proof. I posted a screenshot of her answer.
Just saying.