Student or Learner
1a) You should receive an email about the payment details from Paypal.
1b) You should receive an email from Paypal about the payment details.
2) Once Paypal has received the payment, I will send the items to you.
Is 1a) and 1b) both correct?
Is 2) correct?
Is 1a) or 1b) equally correct? I mean is any one of them better English or more commonly used?
2 is fine.
Note that PayPal contains two capital letters. It's a brand name so you should stick to the way they write it.
Remember - if you don't use correct capitalisation, punctuation and spacing, anything you write will be incorrect.