Welcome to OpenStreetMap and thanks for adding this.

When you add a separate sidewalk to a road, there is also a sidewalk tag on the road which can be updated so that data consumers are aware of it.

You can use the "Pavement" overlay in StreetComplete to update these tags, which can sometimes be quicker and easier than doing it with iD.

https://wiki.openstreetmap.org/wiki/Key:sidewalk