Insert table in paragraph field

There is a plugin  named "Richtext editor" provided by Vuram  Have a look into it.

https://community.appian.com/b/appmarket/posts/rich-text-editor-vuram.

If it's Creating DOCX file try using DOCXS from Dynamic Template.

You can look at few plug-ins form the Appian App Market. 

community.appian.com/.../rich-text-editor

apart from what has been suggested by fellow developers, you can use Styled_Text_Editor_Component being provided by appian from 24.2 OOTB

We still need a lot more detail here.  As mentioned above, we do have the "styled text editor" field (which creates basic HTML in a nice WYSIWYG editor in an Appian interface), but if you mean anything other than the basic text styling available in this field, then you're gonna need to specify what you mean.