Every serial plate, on the job it came from
You shoot the model and serial at install, and the line set and disconnect before the panel goes back on. All of it stays right there on the job, so it is still there when the manufacturer asks in year six.
Tag a plate photo "serial" once. Find it later by job, tag or date, instead of scrolling your phone.

Where HVAC jobs go wrong
Warranty registration needs the plate
Model and serial live on a sticker in a dark closet behind a return. Photograph it once at install, tagged to the job, and nobody has to crawl back in there to register the equipment or file the claim.
"It was running when I left"
Supply and return temps, and the gauges before you pack up. A dated photo of that is the difference between a warranty visit and a callback you pay for yourself.
Four visits a year all look the same
Same equipment, same closet, and no way to remember which spring you changed the capacitor. Open that job again next time, and every visit stacks up in order, dated, so you can see exactly what you did and when.
The install nobody photographed
You inherit a system someone else put in and the homeowner swears it was new last year. Your first photo set becomes the baseline, and every argument after that starts from it instead of from memory.
Run one of your own HVAC jobs through it
Twenty minutes on a call: give us one real job, we load it and tag it while you watch, and the finished PDF and a share link are in your inbox before we hang up. $5,000 once on your own hardware, $3,500 in your own cloud, or $99 a month hosted. unlimited people either way.