If a trust account has co-trustee's. Do they have powers to act individually or do they have to work together? When opening a trust account with co-trustees does it have to be designated as "and/or"?

This is a state-by-state (and possibly trust by trust) issue. Some states have laws creating a "default rule" that applies unless the trust says otherwise. Some states don't say anything. If your state authorizes use of a certification of trust, I would certainly include a representation in the certification about whether cotrustees can act individually.

Sometimes the trust document will state whether the co-trustees may act independently or must act in unison. If the document is silent you next need to turn to the state law that governs the trust. You may also need to look to case law in the jurisdication as some courts have made some pretty specific interpretations of state law.

Unless you have expertise in this area, I encourage you to seek the guidance of your bank's counsel for your specific circumstance.

We have developed a general form that is signed by the Co-Trustees that acknowledges that they can act independently of one another. It's used in cases where the Trust does not specify, but names the Trustees as Co-Trustees.

You really need to check your state's trust laws to determine if it has a statute that says something like:

"Unless otherwise provided in the trust instrument, a power vested in two or more trustees may only be exercised by their unanimous action."

This is how California Probate Code Section 15620 reads.

Why this is important is that under a statute like California's law, the trust agreement must say something about co-trustees acting independently otherwise you have a dual signature requirement.

This type of a statute can become a "problem" if you have a widow/widower creating a revocable living trust which names 2 kids to act as co-trustees after the parent dies. If the parent says nothing about the kids being able to act independently of each other then there is a dual signature requirement. If the parent creates a revocable living trust the parent normally retains the power to amend the trust but the trust becomes irrevocable (and not subject to amendment) after the parent dies.

If the parent did not amend their trust to provide that it only takes 1 trustee to do anything, the form you use cannot be used by the successor trustees after the parent dies. The successor trustees would have to go to court and get a court order changing the signature authority in order to act independently of each other.