Praying

This is how the Gods provide magic to their chosen subjects.

Divine magic⁠, as the name suggests, is the power of the gods, flowing from them into the world. Clerics are conduits for that power, manifesting it as miraculous effects. The gods don’t grant this power to everyone who seeks it, but only to those chosen to fulfill a high calling.

— 5th Edition Player's Handbook

So the gods grant their followers magic effects. These effects are always based on The Weave.

Harnessing divine magic⁠ doesn’t rely on study or training. A cleric might learn formulaic prayers and ancient rites, but the ability to cast cleric spells relies on devotion and an intuitive sense of a deity’s wishes.

— 5th Edition Player's Handbook