A trademark can be any word, phrase, symbol, design, or a combination of these that identifies goods or services. A trademark/service mark identifies the source of goods or services, provides legal protection for a brand, and helps guard against counterfeiting and fraud. Read more about trademark basics.
How to select a trademark that is both federally registrable and legally protectable? This USPTO video: Basics Facts: Selecting a Mark can get you started on the right track.
Review the Trademark Process online to get started on the process.