That would be due to your site being on WordPress.com, you are limited to their options for the classic editor as there are differences in WordPress.com and WordPress.org:
-guide/self-hosted-wordpress-org-vs-free-wordpress-com-infograph/
The latest upgrade of MotoPress is awesome!! User interface is very easy to learn and the row and column control now is great when creating responsive content to your site. This is by far the best plugin for anyone working with a wordpress site. The value of time saved in developing a site with this plugin far outweighs the cost. I would not be without it and the customer service that I have experienced with the MotoPress team is equally awesome!!
This package assumes that your code will run in an ES2015+ environment. If you're using an environment that has limited or no support for such language features and APIs, you should include the polyfill shipped in @wordpress/babel-preset-default in your code.
Unless you're creating an editor, it is recommended that the components in @wordpress/components should be used rather than the ones in this package as these components have been customized for use in an editor and may result in unexpected behaviour if used outside of this context.
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