You can see here which is better, an iPhone 12 or 13:

• The iPhone 13 is expected to last 2.5 hours longer than the iPhone 12, and the iPhone 13 Mini 1.5 hours longer than the iPhone 12 Mini.
• The iPhone 13 starts at 128GB, therefore the price difference between it and a 128GB iPhone 12 is only $50.
• The iPhone 13 and iPhone 12 both have the same camera specifications. The front and back cameras on both phones have 12-megapixel sensors.
• The new camera configuration on the iPhone 13 gives the wide-angle camera a bigger sensor and sensor-based stabilization.
• The iPhone 13's cameras have a new diagonal structure that allows for a larger sensor, while the ultrawide camera's new sensor helps it gather more light.

Read More: How can we take photos underwater with an iPhone 13?