If you received any email with attached PDFs file, you can view it by online by using your browser directly (safari), the iPad mail app supports PDF documents, or you can view the PDF document on your PC or Laptop by synced your iPad with your PC or Laptop. For PC or Laptop, there are some software may you install on your PC that support to view your PDF documents.

Here how to view PDFs from email directly :

Exactly, you can open PDF documents has attached to your incoming email with iBooks app or other apps on your iPad. If you want to view a PDF email attachment, just simple way, tap “Open in iBooks”, on the right top at the corner of your iPad screen. So, the PDF document will open and you can view and read it.

Here how to open PDF document on your PC :

1. Open iTunes on your PC / Laptop.
2. Select your iPad in the Devices list on the left in iTunes.
3. Click the Books tab on your iTunes window.
4. Make enable on checkbox of the Sync Books.
5. If iTunes is set to only sync selected books, be sure to enable the checkbox next to the PDF you want to sync.
6. Click Sync to starting sync your PDF documents and other books between your iPad with your PC.
7. The result will show up on your PC in the iBooks app.
8. Open PDF you want to read.

It’s not too difficult to do this job.