Can users be forced to insert only plain text by default in CKEditor?

Question

I know there is "Paste Text" button in CKEditor, and I can limit allowed HTML tags.
But it's very hard to explain clients to use specific button when they insert text.
As result they often insert "dirt" texts with HTML tags.

As I remember there was setting in early versions of CKEditor to force insert plain text by default but cannot find it in current version.

Is there any solution for the problem?

UPDATE: I don't want to restrict user to use some tags. But user should get "clean" plain text without HTML tags when insert text.

Answer 1

You want to change the ckeditor configuration to always paste as plain text.

This defined in https://ckeditor.com/docs/ckeditor4/latest/api/CKEDITOR_config.html#cfg-forcePasteAsPlainText

It comes down to the following JavaScript configuration:

// All content will be pasted as plain text. 
config.forcePasteAsPlainText = true;

Have a look here for where to set it Is there advanced configuration for CKEditor in Drupal 8?

Or just use module CKEditor custom config and set in custom configuration: forcePasteAsPlainText = true

Answer 2

Eventually I used module CKEditor custom config and set in custom configuration: forcePasteAsPlainText = true