According to the General Principles of the Civil Law and the Contract Law, the premise of the validity of a civil act is that it conforms to the legal provisions, that is, it does not violate the prohibition and mandatory provisions of the law, and it means that it truly abides by the principle of good faith. As long as the signed contract can embody the principle of protecting the rights and interests of all parties, the contractual relationship should be considered valid.

As for whether the parties affix their official seals or sign, it is only a matter of form, because they only affix their seals without signing or only sign without stamping, and there is no opposite determination on the establishment and effectiveness of the contract.

As long as the other party signs, it will have legal or corresponding effect. According to you, all levels of the unit can testify. Therefore, as long as the content of the signed document is legal and valid, it is the true meaning of the unit or individual, and even if there are any legal consequences, she will still be responsible.

I hope I can help you.