How can I give the edges of a line a different color?

Hi,

Like Myra_Ferguson said there are a number of options you could try. Also the Mesh Tool may help.

https://helpx.adobe.com/uk/illustrator/using/meshes.html

If you could show us a screenshot that would be amazing.

I hope this helps.

Sim

There are a few different ways to add another color to the edge of a line depending on what you want to do.

If you want an additional stroke, you can select your path, go to the Appearance panel, click the Add New Stroke button at the bottom of the panel, and change the color, stroke weight, and stroke alignment in that panel.

If you want a contour that isn't necessarily abutting the path, you can go to Effect > Path > Offset Path... and set the offset. If you want the original path plus that offset, add a stroke in the Appearance panel and drag the Offset Path onto the lower stroke. If you are working with a path, the offset will go all around the path--not just to one side or the other. 

You could also make a gradient, set the stops where you want in the Gradient panel, and change the Stroke to Apply gradient across stroke.

Please show.