"how do I obtain a tax id number for a revocable living trust?"
You can obtain a "tax id number" (EIN) online at the link below.
https://www.irs.gov/businesses/small-businesses-self-employed/apply-for-an-employer-identification-n...
Note that revocable living trusts generally do not need an EIN.
See https://www.irs-ein-tax-id.com/learn/faq/trust-need-tax-id-number/
