What are some basic rights that a beneficiary of a parents trust have.
Is a beneficiary allowed in writing copies of wills and or trust paperwork?
When is a trustee required to provide a beneficiary an accounting of the trust?

Thanks in advance for the help!!

Depends on the state law.

In Virginia prior to death or incapacity of the parent you would have no right to see either a will or a revocable trust. You would have a right to see an irrevocable trust if you were a beneficiary.

As for an accounting, it depends on state law.  In Virginia it is annually unless the trust says otherwise.

ETA:  Virginia and 30 other states and D.C. have enacted the Uniform Trust Code.  Nevada has not.  So if you are asking about a trust in Nevada you would need to research the law there.

Not an attorney but going through some Trust stuff now..as beneficiary, Executor of estate, sole heir.
More info.. are both still alive ?
What is the issue ? General.
Depending on the issue ? The answer could involve both State and Federal (IRS) if financial in nature.
Attorney that practices Family Law is most likely the answer.

Dad died 2 years ago mom died 10 years ago essentially making their trust irrevocable.
The trustee my sister has stated that we the beneficiaries won't get any paperwork. That if we have questions we need to ask her.

OP needs to consult with a lawyer in his state.
I'd guess that a beneficiary "should" be entitled to see the trust documents in this situation, so as to be able to ascertain whether or not the trustee is doing her job appropriately, but that's only a guess.

That is a familiar fact pattern for many of my cases.  You need to see a lawyer.

That doesn't sound right.  My mom was a trustee for a trust that benefitted her two brothers after their parents died (long story) and each year they got an annual accounting of how the assets were invested, expenses, disbursements, etc.