I did a post here to show a kit of tools I used to measure an existing house using the iPad, measurement tools, and a camera.
I take that back to desktop to finish the job for multiple reasons; I’m faster on desktop, I use Match Photo for a lot of detail parts (which can only be done on desktop), and there are some plugins that make door and window insertion a little faster. If you get a LIDAR equipped iPad, you can do Scan to Design which is pretty quick, but for inhabited space it picks up all the junk in addition to the building, so I haven’t decided yet how helpful it is. That said, it’s still possible to do plans on iPad if you want.
If your objective is to show someone what it looks like just to put something like a radiator into an otherwise existing space, then Match Photo is great for that. You just model the radiator and insert it into the photo and don’t have to model all the existing stuff. Here’s an example of mechanical equipment on a roof from back in 2016.
Again, Match Photo is not on the iPad or Web version, just the desktop Pro version.