Oh, I have absolutely no experience with .svg files.
Adding a material and changing the look should be straightforward.
To export is like in most software: File > Export. There are many export options available, but not all support materials. And if you open it in some other program, the materials will probably be different, as they probably don’t use Cycles. But I don’t have much experience with exporting either; I try to avoid importing and exporting.
Someone else will probably be of more help.
