Those of you who want to save pictures as JPEG instead of HEIC on the iPhone its very simple.
follow this steps:
1 – Settings
2 – Camera
3 – Formats
4 – Most Compatible (check)
That is pretty much it.

Why would you want to switch from HEIC to JPEG?

because most Apps, Tablets, and Computers don’t work with HEIC format, JPEG is more popular and used by more Programs and Apps.