@ArJay_Hayes the funding instrument types you have access too are:
- INSERTION_ORDER
- CREDIT_LINE
- AGENCY_CREDIT_LINE
- CREDIT_CARD
Each of these are setup by the advertiser, not through you on their behalf. Small business accounts (accounts that aren’t setup through Twitter’s sales team) will generally only have access to the CREDIT_CARD funding instrument.
As you already noted though, in the enum list we do have an additional funding instrument type called PARTNER_MANAGED.
This type of funding instrument does pretty much what you’re describing, but it isn’t available for you to use given the Ads API tier you’re currently in. This funding instrument type is documented, but that documentation is not available to all developers because this funding instrument type is only available on a case-by-case basis for select Ads API partners.
The PARTNER_MANAGED funding instrument is generally only considered for use by large, strategic partners and even then it’s only used in rare and very specific scenarios. For now, you’ll need to use the other funding instrument types available to you through the advertiser’s account.