Preview shows the file. It does not read a table out of it. Extracting Excel from a PDF or a photo is a scan, and you only do that when the file is a table you need as cells.
Open it
- Find the file in Documents. List or grid is only the browsing view.
- Tap a PDF to open it.
- Tap a JPEG, PNG, HEIC, WebP, or GIF to preview the picture.
Tablune is coming soon, on iOS 15.6 or later, with a 7-day trial.
Related: Pull a table out of the PDF · Switch list and grid · Import the file first