As the name suggests, a certified pharmacy technician is licensed or certified by the relevant organization in their state or country. In America, the organization is called the Pharmacy Technician Certification Board (PTCB) and you must complete a course and exam to get certified. Ensure that your certification is valid in the place you are applying to and make sure you clearly list your certifications in your resume.
Aside from being certified, recruiters want to see a history of successfully working in pharmacies and a strong and updated skills section.