Ink is used for seals, and its main function is to affix seals on documents and certificates in order to achieve the purpose of authentication, proof, guarantee or appraisal. Ink is usually used for official documents, contracts, invoices, certificates and other documents that need legal effect. It can ensure the authenticity and legality of documents and prevent them from being tampered with or forged. Inks can be used not only for official documents such as official documents, but also for personal seals, such as signatures and mailing letters. In some cultural traditions, inkpad is also regarded as a cultural symbol, representing power, status and identity. Generally speaking, the main function of inkpad is to ensure the legality and authenticity of documents and certificates and prevent documents from being tampered with or forged.