It sounds like you're experiencing a peculiar issue with your iPhone 13 screen under sunlight. The appearance of horizontal lines and reflected alphabets might indicate a problem with the display
Here are a few things you might consider trying to address the issue:
- Try adjusting the screen brightness to see if it makes any difference. Sometimes, too much brightness in direct sunlight can cause unusual reflections.
- Sometimes, smudges or fingerprints on the screen can cause unusual reflections or patterns. Use a microfiber cloth to gently clean the screen.
- Consider using a high-quality screen protector designed to reduce glare and reflections. Some screen protectors have anti-glare or anti-reflective coatings that could help in such situations.
Given that the issue only occurs under direct sunlight, it might be specific to the interaction of the screen with light in that particular condition. However, if it significantly affects your ability to use the phone, it's best to get it looked at by an expert.

Get a Genius Bar Reservation and Apple Support Options - Apple
When you encounter issues with your Apple devices, the Genius Bar at Apple Retail Stores is the go-to place for expert assistance. The Genius Bar is staffed by knowledgeable Apple employees, often referred to as "Geniuses," who can diagnose and resolve a wide range of hardware and software-related problems. To ensure personalized attention and a convenient visit, Apple provides the option to schedule a Genius Bar Reservation.
Contact Genius Bar.
Manage Reservations - My Reservations - Apple
