A “corporate seal” is a seal much like a notary seal but with the corporate name imprinted on it. In past years, corporate seals were used more frequently to authenticate corporate documents. In my experience, corporate seals are seldom used today. Occasionally, a bank or another institution will ask for your corporate seal on a document. You can usually obtain one at a rubber stamp store or similar business within a few days. My advice is to wait and see if you will really need it. If so, you can get one quickly in most cases. If you decide you need or want one, the link provides a list of companies that sell them. Corporate seals often come as part of a corporate kit. Independently, they sell for approximately $30 to $100, depending on how fancy they are.