Under your shopify dashboard, navigate to "themes" under "online stores" which is under "Sales channels". Here, click on customize button for the current theme you are using. Navigate to the PDP, where you want to change the font.

Now, in the theme editor, click on the app embeds icon in the sidebar, now, search for whatmore in the search field.

Scroll down, and the primary font option appears, now, you can change the font style & font weight.

Click on change button, search for the font you want to use, or scroll down and chose your desired font from the list below, select your font weight with the dropdown icon.

Now, click on select, and your font will be changed for PDP.

Under your shopify dashboard, navigate to "themes" under "online stores" which is under "Sales channels". Here, click on customize button for the current theme you are using.

Now, in the theme editor, navigate to the page which has the video elements, whose font you want to change.

click on the whatmore video element section, and the customize sidebar will load.

Now, scroll down, and title font, primary font option appears. Click on the font which you want to change, here, for example, I'll click to change the title font.

Customization side bar loads, which has the font selection, click on "change" button.

A list of font styles are load, from which you can chose, or you can also search the fonts in the search field.

Select your desired font weight, by clicking on the regular text with the downward arrow, a dropdown appears, out of which, you can change the weight.

Now, click on select, and your font will be changed accordingly.