Outdoor cleaning is mostly about patience and about not damaging the surface in the process. Most of the damage done outdoors is done by pressure washers.
Pressure washers, and when not to
They are excellent on concrete and engineering brick and destructive on nearly everything else. On soft sandstone, block paving and older patios they blast out the jointing sand and erode the surface, which leaves you with a clean patio that grows more weeds than before and starts moving underfoot.
If you use one, keep the lance moving, hold it further back than feels necessary, and expect to re-sand the joints afterwards.
Moss and green growth
Moss and algae grow where it is damp and shaded, so the lasting fix is light and drainage rather than repeated cleaning. A proper patio or roof treatment left to work does more than scrubbing, and works slowly by design.
Moss on a roof is not a job to do from a ladder. People fall doing this every year. Treat it from the ground with a long lance, or pay someone with the right access equipment.
Decking
Sweep the gaps out first, because trapped debris is what holds the water that rots it. Clean with a deck cleaner rather than bleach, which lightens timber unevenly and damages planting either side. Re-oil when water stops beading, not on a calendar.
Weeds in paving
Boiling water works, is free, and needs repeating. Acetic acid products burn the foliage but not the root. Glyphosate is more permanent and more controversial. Whatever you use, keep it off the plants you want and away from anywhere it can run into a drain.