To get a payoff letter, ask your lender for an official payoff statement. Call or write to customer service or make the request online. While logged into your account, look for options to request or calculate a payoff amount, and provide details such as your desired payoff date.
The specific job that you perform doesn't matter, as long as you're employed by a qualifying employer. For example, if you're a full-time employee of a public school system, your employment would meet the requirements for PSLF, regardless of your position (teacher, administrator, support staff, etc.).