Which editor do you mean exactly? Feel free to show screenshots of the relevant section: https://wordpress.org/support/forum-user-guide/block-editor/#adding-screenshots
Either in the WP Bakery Text Editor. or in the main page editor on WordPress Posts ( I disable gutenberg).
These are two completely different tools with different configuration options. WPBakery is also a commercial product, so we can’t tell you anything about it here in the forum. I would therefore recommend that you contact them directly: https://support.wpbakery.com/login
And if it were the normal WP editor?
Based on your description above, you probably mean the classic editor, because WordPress now has another “normal” editor in the standard version, namely the block editor. With the classic editor, it would depend on which option you mean exactly. A screenshot, as mentioned above, would be helpful.
Where you choose Header 2, Header 3, Paragraph, Preformatted.. that dropdown.
I suspect that this will now be difficult, if not impossible. The reason:
WordPress provides the Classic Editor based on TinyMCE 4.9.11. The reason why there will be no update to more recent versions is described here in the Core Ticket: https://core.trac.wordpress.org/ticket/47218
The developer of TinyMCE does not yet provide documentation for versions prior to 5.0. There is a copy of the earlier documentation here on GitHub: https://github.com/tinymce/tinymce-docs-4x
How to use the options in WordPress is described here: https://codex.wordpress.org/TinyMCE
Now look for the “block_formats” that are also mentioned in the example at the latter link. It is mentioned here in the old documentation: https://github.com/tinymce/tinymce-docs-4x/blob/main/_includes/configuration/block-formats.md?plain=1 – I have not seen a way to add your own formats here. It may be possible with some TinyMCE plugin (this is not a WordPress plugin), but you’ll have to search for older versions.
Kind of amazing that it can’t be done.
If you consider this: you build a website for someone. They want to apply custom styles to certain titles. Absolutely no way to enable that to be easy for them.
If you could add code that applies “Custom 1” in the header dropdown to a line, to make it red for example, and Custom 2 to be maybe larger font.
But so far, no way to do that. I’ve never actually thought about it until someone asked me today, and I Thought… why on earth is there not a way to do this?
There isn’t. Baffling really.
See if this works for you https://codex.wordpress.org/TinyMCE_Custom_Styles
I think it is what you’re asking for and would add specific selectors to the format tab. The Header 2/3, paragraph etc.. you mentioned controls the elements, which is not the same as adding a class or style and as far as I know they have all the elements you would want already covered
