There are a few options ..
1. get staff to change in ipad so it saves as jpg not Heic.
2.
Martin Dooling
Try this one - https://tinywow.com/image/heic-to-jpg
3.
Otherwise there is something like iMazing: iMazing Converter | Free Photo HEIC to JPEG and Video HEVC to MPEG-4 Conversion Tool
Though you'll have to figure out the necessary installation stuff (or create a wrapper in something like AdvancedInstaller) so that you can deploy it.
4.
I wrote a simple frontend for Imagemagick for converting images. Main reason was for easy batch converting a large range of image types. Here's a link if you want to try it. There might be some bugs. Never got around to cleaning up the code.
5.
What you want is iMazing Converter, which is free.
This is the exact link for it: Download iMazing Converter for Mac and PC
They even say on the download page for iMazing Converter that it is 100% free.
7.