How to make a Reddot Content Class in WP

I’m migrating from Reddot to WordPress, and am looking for alternatives to Reddot’s content classes (basically forms so the user enters some data, and that data gets inserted into predefined html blocks).

What should I look into to create my own content blocks for users, so that when creating a page they fill in certain fields, and then those fields get inserted into a block of html that gets inserted into the page?

Thanks!