Open the Notes app
Create a new note or open an existing one
Tap the camera icon
Tap Scan Documents
Position the PDF pages in view of the camera
Let the iPhone capture the page automatically or tap the shutter button
Adjust the scan corners if needed
Tap Keep Scan
Repeat for additional pages
Tap Save when finished
Tap the scanned document in the note
Tap the Share icon
Choose Save to Files or send it as a PDF
Open the Files app
Tap the More button
Tap Scan Documents
Scan the pages
Tap Save to store the PDF
Use the Books app or a third-party scanner app if needed
Open the app
Select the scan option
Scan the PDF pages
Save or export as PDF