Registering a business brings several seals with it. The names are close enough to confuse, but each has its own place.
Corporate registered seal (round)
The company's principal seal, filed with the registry office. Used on contracts, certificates and filings. The standard form is round, with the company name around the rim and 印 or a title in the centre.
Square company seal
The workhorse for routine trade documents — invoices, quotations, delivery notes, purchase orders. A thick square border around the company name. It needs no registration and sees far more daily use than the registered seal.
Address stamp
A wide rubber stamp printing company name, representative, address, phone and registration number in one press, so you never write them out by hand. Usually pressed next to the square seal.
The representative's personal seal
Pressed in the representative's own name, on employment contracts and internal documents where the line reads «CEO John Kim (seal)».
Making them as images
All four are available here. Make the corporate round seal, the square seal, the address stamp and a personal round seal once, and most company paperwork is covered.