The "cut and paste" one is familiar with when using a word processor is not available when using the PDF format/technology.
While minor edits are possible with Acrobat major edits can (and do) goober a PDF such that it is no longer usable.
.
So, with PDF content from, say, a Word file you'd have renderable text with gives Acrobat something to work with for those minor edits.
.
However, a PDF containing a scanner's output images provides just that -- images. Images have no text. So, nothing to edit or copy-paste.
.
For scanned images of textual content in PDF use Acrobat's OCR to provide renderable text.
.
The output of Searchable Image and Searchable Image (Exact) is hidden/invisible (the characters have no fill, no stroke). Trying to edit this is problematic.
.
Use of ClearScan would provide an output more amenable to editing. But even with that the content manipulation, as described, is something you'd do with a Word file rather than PDF.
.
Be well...