How to create HDRI texture?

Hi. I like to use HDRIs. I use them when I’m modeling, I use them when I’m painting and of course I use them when I’m rendering. But how to create them?
I found a program which creats them from google maps and I heve an idea how to paint them (just paint an unwraped sphere).
But how actually create them? Can I create them with my cell phone and what programm do I need? Or maybe you know how to write this programm by myself…
And do you know any addons to render HDRI texture? I mean not to render HDRI as a background but to create it from the scene.

Camera tripod, a good camera that can preferably do exposure bracketing, use manual mode, a good wide angle (or fish-eye which I’m using) lens, stitching software. Plus a lot of work, patience and time.

Take a look at this:
How to Create Your Own HDR Environment Maps
or
HDR PANORAMA PHOTOGRAPHY

There is also a free program from Microsoft that will stitch it all together for you. https://www.microsoft.com/en-us/research/product/computational-photography-applications/image-composite-editor/

You can create your owh maps with Blender
https://b3d.interplanety.org/en/making-your-own-studio-hdri-in-blender/