
sham.15714 (Customer) asked a question.
Will Okta honor passing subject as email in authn request and does okta auto fill the username field if we pass subject in authn request? If not, any other way, we can use to auto fill username field in Okta from authn request during SAML sso?

No, this is not currently supported.
You can suggest a feature enhancement on the Okta Community page by going to the Community→ Ideas tab. Features suggested in our community are reviewed and can be voted and commented on by other members. High popularity will increase the likelihood of it being picked up by the Product Team and it being implemented.
More details here:
https://support.okta.com/help/s/blog/a674z000001cj7YAAQ/okta-ideas-faq?language=en_US