How can one share or transfer only part of a big PDF file to someone else, without sharing the entire document?

 One way to share only part of a big PDF file is to extract the pages you want to share and save them as a new PDF document. This can be done using Adobe Acrobat or other PDF editing software. Here's how to do it in Adobe Acrobat:

Open the PDF in Adobe Acrobat.

1. Select the pages you want to extract by holding down the "Ctrl" key and clicking on each page.

2. Right-click the selected pages and choose "Extract Pages."

3. In the "Extract Pages" dialog box, choose where you want to save the extracted pages and click "OK."

4. The extracted pages will be saved as a new PDF document.

You can then send the extracted pages to the recipient as a separate file.