To register a trademark, the mark must be used in commerce either interstate or internationally. Only marks that are used to sell goods/services involving different U.S. states, or involving countries other than the U.S, may be registered as a trademark. Additionally, the mark must be used in association with your goods/services sold. Generally, acceptable use is defined as follows:
For goods: the mark must appear on the goods, the container for the goods, or displays associated with the goods, and the goods must be sold or transported in commerce. The product must be sold/sent across state lines to qualify as interstate commerce. The product must be sold/sent to another country to qualify as international commerce.
For services: the mark must be used or displayed in the sale or advertising of the services, and the services must be rendered in commerce. To qualify as interstate commerce, the service must be provided to those in another state, or the service must affect interstate commerce (for example, hotels or gas stations). The service must be offered to those in another country to qualify as international commerce.