Suspicious App Store purchase emails
The best thing to do is to check your purchase history. 

There are some other things that can identify the email:

Genuine emails will contain your billing address:


  Genuine purchase receipts—from purchases in the App Store, iTunes Store, iBooks Store, or Apple Music—include your current billing address, which scammers are unlikely to have.



https://support.apple.com/kb/HT201679


You should report the email to reportphishing@apple.com


  If you receive what you believe to be a phishing email that's designed to look like it’s from Apple, please send it to reportphishing@apple.com. 



https://support.apple.com/kb/HT204759


Importantly don’t open any attachments just in case, change your Apple ID password like you’ve already done and report the email immediately. You can also block the email.