In order to become a bank teller, one must apply for a teller position. This can usually be done either online or by submitting a resume to the bank (however, you will most likely still need to fill out an application).
Your resume will initially go through an ATS (applicant tracking system) that will grade it and check your match for the position. That is done mainly by parsing your resume to find relevant keywords. Resume scanning tools simulate the ATS action to show you exactly what you can improve in your resume to improve your chances.
After you apply for a bank teller position, you may be asked to interview. If you are invited to interview, be sure to arrive a few minutes early and dress professionally. If you do well on the interview, you may be invited back to take a test to assess your aptitude with figures. Be sure to come to the test prepared.