People often ask me which social security number to use for their trust. Please refer to your specific documents, but generally speaking:
If it's a revocable living trust, then it will probably use your own social security number if you set up the trust, since you're the trustor/grantor/settlor. If you're married and it's a joint trust, then generally speaking you can use either person's SSN. I often recommend to use the healthier person's SSN which might prove beneficial in the long run.
Once that trust become irrevocable, or if it was an irrevocable trust from the beginning, then it probably requires it's own TIN (Tax Identification Number).
Please consult your attorney and/or CPA for your specific situation.
Mike Massey Law can help you with your Last Will & Testament, Living Trust, Durable Power of Attorney, Medical Power of Attorney, Living Will, HIPPA Release, Transfer on Death Deed, Cremation/Burial Wishes, Pre-Need Guardianship, Guardianship preference for Minor Children. Local Texas Attorney/Lawyer may be able to help you with estate planning. Call 512-757-9065 or Email: firstname.lastname@example.org