The brand image and corporate identity can be built up with a well thought and well defined logo. The objective behind the creation of a logo is to develop recognition whether it is your brand or name. Depending upon the uniqueness of the business the logos can be categorized into three types: Text, Symbol and Combination.
Text logos popularly known as Word Mark or Logotype are the simplest of the other logo types. You have an example of Disney, Microsoft, RayBan, Google and FedEx before you. In these cases the logo is very recognizable though it is based on text only. The text itself is iconic and they does not have icons associated with the text. If your business has a unique name such as Google then also text based logos are considered to be effective. These are also good for companies that have multiple ventures or many types of products/ services that may be hard to define in a single picture.
A symbol logo includes only symbols, images, icons ad shapes neither words nor letters. Whenever a Swoosh is seen Nike comes in the mind. You think Apple Computers whenever an apple is seen with a bite out of it. In the initial stages a business uses a combination of symbolic logo and text based logo then when they have enough brand recognition text is dropped. Graphic symbols are often trademarked so that the symbol cannot be copied and no one can use anything that is too similar to your logo.
Most companies who are just starting out use a combination of text and symbol for their logos. In fact it is the most popular one. There are some prominent companies that have a combination logo like Pepsi, McDonalds, and Puma. As the symbol is always associated with the name of company, this makes the logo more unique. Both symbol and text are included together, side by side or with one located above the other.