If you want to protect yourself, you must understand the contract law, and you must not have anything that is obviously unfavorable to the enterprise. For example, if you can't give advance payment, you must not give advance payment, if you can pay after the arrival acceptance, you must not mention it yourself, otherwise you must provide a basis. In addition, purchase vouchers must also be presented in terms of material selection and purchase price (this department should have a strict procurement process). In short, since the leader asked you to do internal audit, you should be responsible for the enterprise, and it is also a good protection for yourself. Of course, you have to meet these requirements before signing. Often at the same time, the most common signature content is: "meets the requirements, or does not meet the requirements, or indicates the specific content that does not meet the requirements."