Yes, you can add your own text to replace the ‘READ MORE’ button text.
However, this should be entered into the ‘Button Text’ option which can be found under the ‘Options’ heading.
The ‘Link’ field is where you can enter a URL to link to, so that you can add your own links to point each featured service to. This is for if you want to enter your own content instead of only being able to select a page to pull the information from as it is in the free version.