There are a couple of ways to handle this. You can use a workaround to convert HEIC images to JPG (or JPEG) on your iPhone, or you can adjust your settings and switch back to shooting photos in JPG.
You’ll find 19 ‘convert to PDF’ tools, with support for images, Office software, and even eReader formats. Converting from PDF offers up 10 options, including PDF to Word, Excel, PowerPoint ...