Fwiw, I do this all on a desktop computer or laptop. It may well be possible on a mouseless smartphone or tablet but would drive me nuts.
Particularly in the desert, these days aerial or satellite imagery from Google Maps and ESRI (Bing, etc – often better than Google) is so good you can spot passing vehicles and whether a road is sealed, a track or even a little used track. This is the sort of age-sensitive information you won’t always get from maps, be they digital or printed. When planning new off-road routes, I find tracing the probable route in advance helpful for all the obvious reasons. It also gives a good preview of the area and what features I might come across (mineral mines; climbs, gorges, junctions). Using Google satellite mapping services, tracklogs can be drawn, saved and exported in two ways: Using Google Earth Pro – no Google account needed but your annotated maps won’t be automatically saved online/in the cloud. I’ve drawn tracklogs using this method in Moroccan hotel rooms prior to setting off along remote tracks (above left), benefitting from the reassurance of knowing a track exists and where the junctions are. See the images and captions below for more.
With a Google account (…@gmail, etc) you can save your routes on a Google ‘My Map‘. It can have as much detail (tracklogs and waypoints) as you like, but Google ‘My Maps‘ are limited to about 10 layers. Layers are a bit like folders (with infinite capacity) and sometimes you have to shift tracklogs or waypoints into a pre-existing layer to free up a new one. This map can be shared or exported but will be saved online and be viewable/editable wherever you have internet (unlikely in the desert).