Remove “Current Volunteer Sing-up Sheets” header

Please read the documentation:
https://stephensherrardplugins.com/docs/pta-volunteer-sign-up-sheets-documentation/
See the section on “All Available Shortcode Arguments” where you’ll find the shortcode argument to change that title.

Header sizes can be changed by simply adding CSS targeting the elements you want to change. Basic HTML/CSS stuff. Inspect the element in your browser to find the selector to use, then add some CSS to the “Additional CSS” section of the WordPress Customizer.

Would you be able to provide the CSS to change the font size?

Also… How to I purchase the “groups” add-on?

Groups extension, and all others, are on my web site. Here’s a direct link to that extension:
https://stephensherrardplugins.com/plugins/pta-volunteer-sign-up-sheet-groups/

You should really spend at least an hour or so to familiarize yourself with basic CSS if you are trying to run a website.

The default sizes for those headings will be determined by your theme. They are H3 and H4 headings. So, if your theme already has a setting for font sizes of headings, you could modify the size there to change them globally.

Otherwise, you use the inspection feature of your browser to figure out the selector. I have added class names to almost all output my plugin generates, so it’s easy to select just a specific header or element from my plugin if you don’t want to change font sizes globally.

The classes for those two selectors are both pta-sus and user-heading (two classes). You could use either one of them as a selector to change font size like this:

h3.pta-sus { font-size:16px;}
h4.pta-sus { font-size:14px;}

You can set the font-size to whatever you want, with any acceptable units (do a search… it’s very easy to find all the options, and many tutorials).

Do you have a good tutorial website?

Google