Site Title Block
The Site Title Block allows you to add or update the title for your site. Adding this block to your content will display the site title and will be more useful once you can edit your Theme’s templates. The Site Title automatically includes a link to your site’s homepage.
The site title is typically the name of your site. The title is quite often displayed in the site header if you haven’t uploaded a site logo, but that depends entirely on your theme. The title will also be used for SEO purposes and can be displayed in search results or on the browsers tab. The Site Title can also be changed on the Settings > General page.
Once you've added the block, there are further options available in the Settings Sidebar including an option to select the font size, and background color.