Form LIBC-337, a Supplemental Agreement for Compensation for Disability or Permanent Injury, can modify Form LIBC-336, LIBC-338, LIBC-495, or an award. Pennsylvania workers' compensation has a form for just about anything you can think of.Here is a list of the 7 most common workers' compensation forms. Instant access to fillable Microsoft Word or PDF forms. Minimize the risk of using outdated forms and eliminate rejected fillings. A Pennsylvania employment contract is a written agreement that establishes a working arrangement between an employee and an employer. Common Legal Forms Used in Claims for Workers' Compensation in Pennsylvania. We have compiled links for the most common downloadable forms, guides, and applications with regard to workers' compensation in Pennsylvania.