The Magic Plan app for iPad and iPhone deserves to have “Magic” in it’s name.
I recently helped an Arlington, VA, customer who had a new iPad and had just moved. They wanted to build a floorplan of their place. Using Magic Plan allowed us to create a floorplan quickly by clicking on the corners of the rooms. You align the rooms, add in windows, make a few adjustments to the estimated dimensions if needed, and you’re done. Once you get used to it, you can have a house done in under an hour.
Then you can even add in furniture to your floor plans or see what it looks like if you do a construction project and knock down a wall.
The app is free to use and requires a subscription if you want to export PDF files for use by an architect.