All of these are in your account settings, in the app or on the website.
Email address
Change it in your account settings. Your orders and eSIMs stay with the account, so nothing needs moving. Confirm the change from the new address when we ask, otherwise the old one stays in place.
Password
Change it in your account settings. If you signed up with Apple or Google, there may be no password to change, and you sign in with that button instead.
Currency
Change it in your account settings before you order. The catalog re-prices and checkout charges in the currency shown. Note that any wallet balance stays in the currency it was added in. See "Wallet balances in more than one currency".
Language
Change it in your account settings. This affects the app and the emails we send.
What does not change retroactively
Invoices already issued keep the details that were correct at the time. If you need one reissued with new details, see "Add a company name and VAT number".