How to sign SAML Authn requests?

I am trying to set up SAML authentication with Quickbase and am working with an IdP that requires Authn requests to be signed. I can see in this article:

https://community.quickbase.com/blogs/quick-base-team1/2021/12/08/saml-public-authentication-certificate-for-signed

that there should be some option to enable signing SAML Authn requests, but I am unable to locate it. Could someone point me in the right direction?