1, Login your cpanel panel Or FTP Panel.

2, Choose File Manager option from Files Tab

3, Open header.twig file Go to /home/test/public_html/catalog/view/theme/OPC202_01(Theme id)/template/common and Right click on header.twig file and select Edit option.

4, Add  new google font link. For find new Free google font see below steps.

5, Type google.com/font in your browser URL and Find new font in searchbar and click on styles.

6, select different font styles like Regulat 400,Bold 700, Black 900 and click on Embed Tab and copy link and paste in head.twig file.

7,  Open stylesheet.css file Go to /home/test/public_html/catalog/view/theme/OPC202_01(Theme id)/stylesheet and Right click on stylesheet.css file and select Edit option.

8, Find Old font name and replace with New font and save file.