Hello,

Easiest way to add some custom font is with CSS @font-face. Paste following code into Appearance > Customize > Additional CSS:

@font-face {
font-family: 'MyWebFont';
src: url('webfont.eot'); /* IE9 Compat Modes */
src: url('webfont.eot?#iefix') format('embedded-opentype'), /* IE6-IE8 */
url('webfont.woff2') format('woff2'), /* Super Modern Browsers */
url('webfont.woff') format('woff'), /* Pretty Modern Browsers */
url('webfont.ttf') format('truetype'), /* Safari, Android, iOS */
url('webfont.svg#svgFontName') format('svg'); /* Legacy iOS */ }

and set absolute paths to your font files, and make sure that you have several different file formats because different file formats will be loaded by different browsers. This is important and more can be found in this article https://css-tricks.com/snippets/css/using-font-face/

Finally style desired elements with css code, so some basic knowledge is required for that part. Example:

body, h1 {font-family: 'YourFont', sens-serif;}

Please understand that this won't add font to the list inside Theme Options > Fonts.

Or you could try Use Any Font plugin, some customers have suggested it but we haven't tested it ourselves.

Neither one way adds font to the list inside Google fonts Options but you will have to use it through custom css code.

For any other issue you are facing please feel free to ask us and we will assist you as soon as possible. I will give my best to help you building your site.

Thanks & Regards, 
Vladimir