It is possible to add 3-d party font for website like in this article: https://css-tricks.com/snippets/css/using-font-face/
Here is the list of necessary files:
webfont.eot webfont.woff2 webfont.woff webfont.ttf webfont.svg
When you will mount all necessary files in fonts folder, please click WP Dashboard => Appearance => Customize => Additional CSS and paste this code here:
@font-face {
font-family: 'DecimaProLight';
src: url('http://www.cstclima.it/wp-content/themes/mytheme's_folder/fonts/DecimaProLight.eot');
src: url('http://www.cstclima.it/wp-content/themes/mytheme's_folder/fonts/DecimaProLight.eot?#iefix') format('embedded-opentype'),
url('http://www.cstclima.it/wp-content/themes/mytheme's_folder/fonts/DecimaProLight.woff2') format('woff2'),
url('http://www.cstclima.it/wp-content/themes/mytheme's_folder/fonts/DecimaProLight.woff') format('woff'),
url('http://www.cstclima.it/wp-content/themes/mytheme's_folder/fonts/DecimaProLight.ttf') format('truetype'),
url('http://www.cstclima.it/wp-content/themes/mytheme's_folder/DecimaProLight.svg#DecimaProLight') format('svg');
font-weight: 300;
font-style: normal;
}
h1, h2, h3, h4, h5, h6 {
font-family: 'DecimaProLight' !important;
}
body {
font-family: 'DecimaProLight';
}
As you understand, please use instead of DecimaProLight the name of your custom font.
Save all changes and check results at the front-end.