Logotype is the stylized font and sign composition containing the name of company, product or service.
Trademark is the identification of graphic objects, which is unique for every individual company.
This is the sign for your potential customer to recognize you from many other companies.
Symbols or logos are guided to the target audience and emphasize the individuality of your brand.
Ideally should be combined both.
From the main parameters (the concept of positioning, naming and sign with the logo) are being built all the other elements of corporate identity as a major advertising and marketing tools to promote your company.