change the font

I want to change the font.
The current theme’s fonts are applied by inserting the following code into the plugin named ‘WP Google Fonts’.

@import url
(“https://fonts.googleapis.com/earlyaccess/nanumgithic.css”);
Body, h1, h2, h3, h4, h5, h6, li, p, {font-family: “Nanum Gothic”, “NanumGothic”! Important;

I want to apply the font used in the theme to the button.
What should I do?