Quick Answer
Go to Settings → Camera → Formats → Select "Most Compatible"
Your iPhone will now save photos as JPG instead of HEIC
Simple 4-Step Guide
1
Open Settings
Tap the gray gear icon
2
Find Camera
Scroll down and tap "Camera"
3
Tap Formats
It's at the top of Camera settings
4
Select Most Compatible
This makes your iPhone save as JPG
⚠️ Important
This only changes how your iPhone saves NEW photos. Photos you
already have in HEIC format will not automatically convert.