Thanks for your answer. This may depend on what e-mail program or app is used.
My test:
(1) On Windows Live Mail: right click the e-mail, then click properties, can see the reply-to email address is the customer's e-mail address. Or click reply button, then right click customer's name, choose Edit Contact I can see the customer's e-mail address.
When I send out this reply, I can receive at test-customer's address, that means, although I can not see customer's e-mail address, but the customer can receive my reply.
(2) On Windows 10 Mail App: In no way to see customer's e-mail address, even I choose add contact, I will have my store e-mail address added, but with customer's name.
When I reply, I receive this reply at my own e-mail address, no e-mail received at test-customer's e-mail address. That means, if I work on windows 10 mail, I will not be able to know who send me enquiry, and not able to reply either.
(3) on Android phone, tested original mail app and Gmail, in no way to see customer's e-mail address unless press reply then the customer's e-mail address will show correctly at 'TO' line.
So if I don't take any action, just read the enquiry e-mail, I can not know who send me this enquiry, just like somebody use my e-mail address send to my e-mail address. This is really not convenient, not mention the Windows 10 Mail problem, I just tried again, I can only reply to myself.
Is it possible to change it and make it just like before, directly show customer's e-mail address?
Thanks.