If you’re uploading .svg files to the WordPress Media Library, you might have been unable to, seeing the error “Sorry, this file type is not permitted for security reasons.”
Open your .svg up with a text editor and check that the first line shows as
<?xml version="1.0" encoding="utf-8"?>
If it doesn’t, whack that in, save the document and try again. Adobe software often omits the xml declaration if you optimise the svg output. Pop it back in, problem solved.