Configuration that matters.
GENERAL
Your business address, which affects tax and shipping Currency, and where the symbol sits Which countries you sell and ship to
THAT LAST ONE
Set it deliberately. Selling to countries you cannot ship to produces orders you must cancel.
PRODUCTS
Measurement units Whether reviews are enabled Stock management
STOCK
Enable it if you hold stock. Set a low-stock threshold.
Decide whether to allow backorders.
ACCOUNTS
Whether customers must register or can check out as guests.
Guest checkout converts better. Allow it unless you have a reason not to.
EMAILS
Check every transactional email. Set the sender name and address.
Test that they arrive.
THE SENDER ADDRESS
Must be on your own domain, with SPF and DKIM configured, or order emails go to spam.