I go to the Protect tab, choose the option "Mark for Redaction>Text&Images" and select the contents that I want to redact. However, when I try to select the "Apply Redactions" button under "Mark for Redaction", it is grayed out (disabled). In short, even though I have already selected the contents that I would like to redact in Foxit PDF Editor Pro, the "Apply Redactions" option is still grayed out.
This issue is likely related to the specific document you are working on. If the document is a digitally signed PDF file, it cannot be modified anymore, which is why it is not possible to apply redaction to this type of PDF file.
To determine if a document has a digital signature, you can view it in the signature panel, as demonstrated in the screenshot below:
To check whether the "Modify Document" is allowed or not allowed in a PDF file, please refer to the following screenshot:
If your document is not a PDF file with a digital signature included, but you are still unable to apply redaction, please share the original PDF file with the Foxit support team for further analysis. You can submit a ticket by clicking here and attaching the file.