Yes, you can use power washers on patios. However, make sure you are using the right washer for this area.
There are different kinds of patios, and your specific patio can mean you’ll need to make some changes for your washing.
For example, you can clean most patios at up to 3000psi or 200 bar. This is for solid patios. But some patios have sand that fills in the gaps between the slabs. In this case, a highly pressurised jet stream may disrupt the sand, causing damage to your patio. By simply reducing the pressure and not focusing the stream on the sand, you can avoid damage to your patio.
Washers that are both electric or petrol can be used on your patio. If you are concerned about your patio, you can always start at a lower pressure and increase as needed.