I tend to use a note taking app and draw sizes onto photos so that I’ve got the information to draw a plan from quickly/easily later and keep it together with any notes/actions that aren’t just measurements (beware randy dog, smells like body buried under floor etc). If you’re using a tablet anyway then any note app you like that gives you quick access to the camera.
Non of them get me to the camera and back again as I’d like – but Notability does an OK job – what I’d like (app developers if you’re listening*) is to open a frame on the note page that IS a camera and take a photo within the page – rather than click out to a camera take a photo and click back to the page.
If its on a phone there are a few apps that speed that up by readily creating a line with arrows on that you add a value to – like ‘Photomeasure’
But I find working over photos more effective than drawing a plan in situ if you’re working quickly and the photos allow you to see if theres important details other than basic dimensions that you’ve missed. I’m usually discussing a plan of action whilst taking the measurements so having the pictures, sizes and notes all on one screen stops details getting missed
* I keep dropping hints but no bloody app developers have developed the ‘Satnav where the accent changes as you travel’ feature I desperately want.