This example shows how to force plain text paste.
<div id="entry-paste-plaintext"></div>
const app = Redactor('#entry-paste-plaintext', {
paste: {
plaintext: true
},
content: [
'<p>Paste rich content here — only plain text is inserted.</p>',
'<p>Try pasting from Google Docs or a web page.</p>'
].join('')
});