Enabling Terms and Conditions via API: User Creation or Post-Creation

Maybe you can clarify a bit, but I would assume you want to set "terms accepted" when creating a user via API, kinda like this checkbox from the OOB registration form?

If that's the case, unfortunately I'm not aware of any way to do that via API

The form key for this checkbox is userAcceptsTermsOfService but that would probably only be useful if you try and replicate the form (which is tricky because of how Khoros handles form submissions of their OOB forms with a bunch of cryptic fields, lia-action-tokens and a generally very opaque way of doing things)... I'm not even sure if the "terms accepted" is persisted anywhere on user level, I've never seen it used or returned anywhere, maybe it just serves as a validation-blocker, so you can't submit the registration form if that checkbox is not checked? E.g. maybe you wouldn't need to store this via API anywhere when re-building a custom registration form via API?

luk , 
T&C is a mandatory check box for us. If we create user via REST API then user had go through the user registration page to accept T&C for the first time visit. We would like to avoid this since the user created through API.

Well, even if you create them via API there is some sort of UI the users would interact with first, or not? I mean they'd also have to define a username (at minimum)... so maybe if you could elaborate on your specific user registration flow it would help come up with potential ideas to solve this because as far as I know T&C is not something exposed (or even stored) at user level, but that is of course just my limited knowledge of the platform, maybe someone from Khoros could confirm or elaborate...