I think that by "trust certificate" you mean a "certification of trust." [I don't know the term "trust certificate".] A certification of trust is basically a shorthand version of the
full trust document. The certification omits the beneficiary and other personal provisions of the trust. The certification gives the name of the trust, proves that it has been signed and notarized, and is in legal existence. A certification is often used to demonstrate to a financial institution that a valid trust exists.
Many states have laws requiring that certain specific information be contained in a certification of trust. You can find a list of these laws in Make Your Own Living Trust (written by me) or The Executor's Guide, both published by Nolo.
Some states also have laws that require the successor trustee of a living trust, who takes over after the person who set up the trust dies, to notify trust beneficiaries (and sometimes other heir as well) of the trust's existence and offer to provide a trust copy to any beneficiary who asks for one.
I do not know if you are a trust beneficiary here, nor if the state where the trust is in has such a law. If you are a trust beneficiary, you need to do some legal research (or hire an attorney to do it) to determine if your state law gives you the right to obtain a copy of the trust. If you state has no such law, there is little you can do, beyond asking the successor trustee, to obtain a copy of the trust.