Go to your board of pharmacy’s website to research the requirements for pharmacy technician because state laws vary greatly. The requirements to take the exam are usually the following: high school graduate, at least 18 years old, and no felony on your record.
If your plans are to become a pharmacist (Pharm.D.), working in a pharmacy is good experience before pharmacy school. Some states will let you work as a pharmacy clerk or tech without any certification. It may be difficult to find a job without certification, but if you can find one without it, save your time and money. Keep in mind, many chain pharmacies and hospitals will not hire you unless you are a certified technician.
For formal training, you will want to look into different programs. In most states, attending formal education (in a school) is not required to receive certification; however, attending a reputable technician program will provide you with the skills needed to succeed. There are several pharmacy technician schools online, but make sure you do your research as many are scams or provided less than par education.
The PTCB (Pharmacy Technician Certification Board) to certification exam (PTCE) or the separate entity, the Exam for the Certification of Pharmacy Technicians, offer the license exam. Some states may not accept one or the other. The PTCE focuses on hospital pharmacy technician practice. Pharmacy technicians usually work with staff pharmacists who are responsible for filling prescriptions and preparing IV bags. I studied mostly the techniques, laws, and calculations (memorize the unit conversion factors! oz->lb, gallons-mL, etc.). I was able to pass the exam without knowledge of very many drugs. Focusing on laws and calculations (and some knowledge of responsibilities) will help you pass. I took the PTCE in California. Generally speaking, a single well-written review book should be enough study material to pass the exam. Read through the book and make sure to complete all of the practice problems, as they are very similar to the actual test. College pre-pharmacy study as little as a day or two and can still pass the exam. Personally, I studied 6 hours a day for 4 days.