When writing official declarations, affidavits, or an employment contract (สัญญาจ้าง), standard Thai pronouns are replaced by a highly formal register. The first-person pronoun "I" or "me" becomes ข้าพเจ้า. This is gender-neutral and exclusively used in formal written or scripted contexts.
To specify that an agreement or statement must be done "in writing," use the formal phrase ลายลักษณ์อักษร.
Parties in Legal Agreements
In contracts, people are referred to by their official roles rather than personal pronouns. Common roles include the employer or client (ผู้ว่าจ้าง), the contractor or employee (ผู้รับจ้าง), and any appointed representative (ผู้แทน).
You will also frequently see the formal auxiliary verb พึง (should / ought to), which carries a strong moral or legal expectation.
General References
Rules and laws often apply to people in general. The noun บุคคล refers to an "individual" or "person" (this can mean either a natural human or a legal entity). When stating "anyone" or "whoever," use the formal pronoun ผู้ใด.
In these contexts, you may encounter formal verbs outlining behaviors, such as ละเว้น (to refrain / to omit).
To add additional points or clauses in an official document, use อนึ่ง (furthermore / moreover). This serves as a highly formal transition, often used before detailing mandatory rules or a regulation (ข้อบังคับ).