Changing "highway" display

I am using the open street map to highlight public access routes, such as permissive routes. These routes aren’t that obvious visually, so I’d like to edit the image used for them.

For example.
Highway=Bridleway to show a thicker, purple line. I want to do this across every approved bridleway, can this be done easily?

If not, is there a way of creating an overlay file to isolate all of this data and do something external instead?

For some simple edits, I’ve found it working fine to just download the SVG (or some other format) using the “Share” button on the right side, and just make changes in an image editor.

If you’re looking for something a bit more sophisticated to build your own map style (even if it’s just a few tweaks to an already-existing map style), then you probably need to configure some software or library. The wiki lists some suggestions:

There are several web-based software options out there too of course. I’ve heard of uMap and MapTiler, though I haven’t yet had a chance to try them myself, and I’m guessing there are a ton of others out there as well.