There is no standard set of forms for these motions/petitions. These are legal documents that need to be drafted to suit a particular client's situation. Expunctions are covered by Code of Criminal Procedure, Articles 55.01 and 55.02. A petition to expunge should track those sections. A motion for non-disclosure to seal a deferred adjudication probation needs to track Government Code 411.081.
There are several different actions to remove records. It depends upon the dispositon of the case and what one is entitled to by statute. You mentioned sealing a record. Sealing a record is something done in juvenile court and is parallel with an expunction for adult records. There is also an action called, nondisclosure, which is does not expunge records. It only makes them not available to private persons and entities-the government can still see the records. Nondisclosures are sought after certain deferrred adjudication community supervisions are successfully completed and terminated, but not all cases are eliigible and the statutes must be tracked to dertmine eligibility.
With an expunction, a civil lawsuit is filed in the civil district court (or district court if the is not separate civil and criminal courts in county with proepr venue). One is not entitled to an immediate expunction unless a not guilty was obtained or the grand jury returned a no bill in the case. in cases that have been dismissed, yuo will have to wait for the statute of limitations to expire before the suit can be commenced.
Expunctions, nondisclosures and the sealing of records are not trivial matters that can be addressed with simple forms. They are in fact complicated detailed legal actions that need professional legal direction. If the order is not properly worded or if not all of the agencies are listed in the petition/motion, then effect of the order could be null. This is whay the petitions, motions, and orders must be tailored to the specific case and situation by an attorney.
The comments from Mr. Walcut and Mr. Vance should be taken to heart. However, considering that you are a paralegal student, have a visit with the Dallas County District Clerk they may be able to show you an active petition and give you a list of agencies that are usually noticed in that County. That being said, an attorney has to be very careful when drafting a petition for expunction. Recently an attorney in Northern Texas was indicted for tampering with a governmental record because he did not check his facts in the verified petition he filed on his client's behalf!