The main component of actually applying to PA school is the CASPA (Central Application Service for Physician Assistants). Almost everything is encompassed in the CASPA. Create an account, and fill out each section of the application. You will select programs and pay for the applications from the CASPA website.
CASPA opens at the end of April each year. Before it opens, have as much prepared in advance as you can. It will speed up the process by having letters of recommendation, your personal statement, and experience descriptions ready to enter. Make sure you also order a copy of your official transcript for yourself; you will use this when inputting your courses into that section of the CASPA. There is an option to pay someone from CASPA to input your coursework for you. This can save time and ensure they are accurately entered, but because of the extra cost I opted to fill in coursework on my own.
When completing the application, apply early and pay attention to detail. Follow all instructions and read the FAQ section if you are unsure of anything. There is also a way to contact CASPA if there is anything that is not answered by the FAQs.
After finishing every section and checking for accuracy, you will finish by paying the fees for applying and sending off the application. Once CASPA is submitted, you are almost finished. The last step for some programs will be the supplemental applications.