Hello,
Using removeWordContent (https://www.phpdocx.com/api-documentation/docx-path/remove-elements-in-docx) you can remove contents for all view modes of the document.
If you want to hide contents when a document is printed but show them in normal view, you need to apply vanish style using DOCXCustomizer (https://www.phpdocx.com/api-documentation/docxcustomizer/customize-docx-Word-documents-PHP) available in phpdocx Premium licenses.
Regards.