Step 01: Go to https://fonts.google.com/ and select you font.
@import code, which should look something like this:
Step: 02: Go to site File manager-> theme/edvik/style/style.css and replace the @import code at the top of your CSS file with existing @import link.

Go to site File manager-> theme/edvik/scss/pre.scss and replace the :root CSS with updated CSS:

Step: 03:
After that, you will notice that the font on your site has changed.