The reason you might be unable to share text in Adobe Acrobat can be due to a few possible issues:

Security Restrictions: Adobe Acrobat allows the creator of a PDF to apply security settings that limit what others can do with the document. If the document has restrictions in place, such as not allowing text extraction or copying, you won't be able to share the text like "8171Bisp.Pk".

Document Type: The type of PDF document matters. If it's a scanned image or a PDF created from a scanned image (a non-searchable PDF), the text won't be selectable because it's essentially just a picture of text.

Document Permissions: Check if the document's permissions allow for text extraction or copying. If the author restricted these actions, you won't be able to share the text.

Outdated Software: Ensure you're using an up-to-date version of Adobe Acrobat. Older versions might have limitations or issues that prevent text sharing.

To address these issues, you can try the following:

Check Permissions: If you have the necessary permissions to edit or copy text, you can usually do so by selecting the text with your mouse and then copying it (Ctrl+C on Windows or Command+C on Mac).

OCR (Optical Character Recognition): If the PDF contains scanned images of text, you can use OCR software to recognize and extract the text. Adobe Acrobat has OCR capabilities, or you can use dedicated OCR software before importing the document into Adobe Acrobat.

Contact the Document Author: If you believe the document's restrictions are unnecessary, you may need to reach out to the document's author and request an unrestricted version.

Update Software: Ensure your Adobe Acrobat software is updated to the latest version to benefit from bug fixes and improvements.

By addressing these factors, you should be able to determine why you can't share text in Adobe Acrobat and take the appropriate steps to resolve the issue.