The primary function of the partnership is to designate Okta as Plaid's vendor of choice for building the authorization system that connects a financial institution to Plaid. This integration, built on an open source standard called OAuth, allows users to connect their bank, credit union or other financial accounts with third-party financial apps without sharing their account passwords.
Plaid already uses the OAuth protocol to connect to partner firms — those with which it has data sharing agreements — and the deal with Okta does not change anything for those companies. The change is targeted toward financial institutions with which Plaid has yet to partner.
https://www.americanbanker.com/news/plaid-partners-with-okta-to-ease-banks-onboarding-process