The iPhone 15 is water-resistant with an IP68 rating, which means it can withstand being submerged in water up to a certain depth and duration. However, Apple does not recommend using the iPhone 15 in the shower or exposing it to high-temperature or high-pressure conditions, such as steam from hot water.
Using your iPhone in these conditions could lead to damage from moisture or heat, and it may not be covered under warranty if it experiences water damage. For optimal safety, it’s best to keep your iPhone away from the shower and moisture when possible.