When a member checks out for a paid tier on your publication, an email receipt for their payment is not automatically sent, unless this option is enabled within your Stripe account.
To enable automated receipts, you will need to login to your Stripe account, and toggle Successful payments on, in your Customer emails settings.
Note that Stripe only sends receipts for successfully completed payments. If the member’s payment fails or their card is declined, a receipt would not be sent.