On what pages is a custom font used? 

Typically, your custom font is assigned to Heading 1 or Heading 2 for any pages. These are meant to be headlines and sub headlines. For Squarespace 7.1, there are 8 font seats in your universal site settings.

How many fonts does Squarespace offer without adding CSS?

There are over 500+ fonts available in the your site styles design settings, including Google fonts and Adobe Fonts. You can read more about this here.

Is there an extra fee for the custom font? 

Yes, there is an extra fee for custom fonts. A one-time fee of $20–$30 is typically required to purchase a webfont license from font marketplaces like Creative Market. This license allows you to use the font on one website. Check the details of your website package to see if a custom font is included or if it needs to be purchased separately before your project start date. If you're interested in using a unique font for your brand, I can guide you through the selection and licensing process to ensure it's properly integrated into your Squarespace website.

How is a custom font added to my Squarespace website? 

A custom font is added to your site settings with code snippets placed in the CSS area  of your settings. Once installed, it lives as a backend setting change in Site Styles. 

What are the words for the creative license one time fee? 

Webfont is a licensed font that can appear in multiple websites owned or controlled by  the Licensee. Pageview limit agreed upon at checkout. Can be used for Web app and  website usage Only displayed in the Licensee’s website(s), within the agreed upon  pageview limit. Embedding fonts Only within the Licensee’s website(s) and agreed upon  pageview limit.Cannot be used for Games, Design or Print-on-Demand applications,  Desktop use. 

https://creativemarket.com/licenses/fonts