You are correct, it is a phishing attempt. Opening the PDF file is not a problem.
- Apple does not include document, or PDF files to download.
- Apple would not refer to you as Dear Customer, Dear Client, or anything other than the name on file for your account.
- Apple would not have such horrible spelling or grammar.
- Apple would not send a message to “Undisclosed Recipients”.
It is a phishing attempt. Do not respond. Do not divulge any personal or financial information. You can use the address below to forward the suspect email message, as an attachment to Apple.
reportphishing@apple.com
If you provided your Apple ID and password at the bogus site, change your password immediately.
https://support.apple.com/en-us/HT201355
The links below have information to help identify fraudulent emails.
Identifying legitimate emails from the iTunes Store
https://support.apple.com/en-us/HT204759