Implement knowledge based authentication (KBA) signature for sharepoint online documents

i need to have my clients sign some forms. the electronic signature must be with KBA / knowledge based authentication.

I want to initiate signature requests from within the teams interface, and also want them to sign a form during onboarding.

What are the possible options (within Office 365 or third party tools), to implement KBA signature for documents inside SharePoint sites? for client inside the US and outside the US.

Thanks