1. Account and domains

Paste the External Account Binding (EAB) credentials you were issued, then say which names the certificate is for.

External Account Binding required

Used for the ACME account and expiry warnings.

One per line, or separated by spaces or commas. The first becomes the common name. Wildcards (*.example.com) need DNS‑01 validation.

Advanced

ECDSA P-256 suits almost everything and is the default. Pick RSA only if something in the chain cannot handle an EC certificate.