There are at least two types of federal trademark applications. The first is a use-based trademark application, also known as a section 1(a) application corresponding to the section of the law that authorizes the application. The second type is an intent-to-use application also known as a section 1(b) application.
A use-based application is one where the applicant is already using the mark in commerce at the time when the application for federal trademark registration is filed. Use of the Mark in commerce can include shipping or selling the goods with the mark or rendering services after advertising those services with the Mark.
An intent-to-use application is one where the applicant has not used the mark in commerce or business at the time that the application is filed. The intent to use application allows the applicant to reserve a trademark that they intend to use before actually using it.
This allows the applicant to stake a claim to rights in a name (or other mark) while doing the work that is required to bring the product or service to market. Many preliminary matters such as purchasing supplies, designing logos, designing graphics, designing packaging, and so forth may need to be completed before the product or service can be put on the market. Such activities might require a substantial lead time between the time when the trademark is selected and the time when the products or services are provided. Therefore an intent to use application allows an applicant to reserve a mark so that they do not have a problem running into others who are attempting to register the same or similar name while there working on their product/service start up activities.
A use-based application is for those already using the mark and an intent-to-use application is for those who plan to but are not yet using the mark.