receipt for PUBG Mobile-a scam?

It’s a phishing attempt. You did the right thing by not clicking on any of the links.

Avoid phishing emails, fake ‘virus‘ alerts, phony support calls, and other scams

https://support.apple.com/en-us/HT204759

You don’t need to do anything. On iOS devices, just clicking on a document won’t install anything nefarious - it’s not possible. The only concern would be if the document linked to a website and you gave private information there, but you did not too that, so you’re fine.

I did click on the PDF link. What should I do now?

Thanks for your help.