I'm planning on trying to get my certification, which exact type of certification should PT's get? Also, would anyone suggest doing it online or just do it through classes?
Don't do it online. You will still have a mandatory classroom portion for the practical application, which can't be done online. I have the AHA BLS for healthcare providers (CPR & AED). This is pretty standard for PT's. The certification is good for 2 years. If you are planning PT school in the near future this will satisfy the school's requirement.