A more thorough explanation:

Redaction is when you go back and edit a document to remove information that needs to be kept secret. This is often done by lawyers to protect their clients' privacy. For example, if a lawyer is working on a case and they have a document that has sensitive information about their client, they might need to redact that information so that it can't be seen by anyone who shouldn't see it.

When you redact something, you don't just put a black box over the text. You need to use special software or tools to make sure that the information is really gone. For example, if you just put a black box over some text, someone might be able to use a computer program to remove the black box and see what's underneath. That's why it's important to use the right tools to redact information.

One example of redaction is when a government agency releases a document to the public, but they need to remove some information from it first. For example, if a document has the name of a secret agent on it, they would need to redact that name so that it can't be seen by anyone who shouldn't see it.