xrpl-dev-portal/content/_snippets/tutorial-sign-step.md

The most secure way to sign a transaction is to do it locally with a signing library, such as RippleAPI. Alternatively, you can sign the transaction using the sign method command, but this must be done through a trusted and encrypted connection, or through a local connection, and only to a server you control.

In all cases, note the signed transaction's identifying hash for later.