You can begin the application process by going to PMI Certifications and starting a new application. Please also read the PMP Credential Handbook available in pdf format at the PMI website.
We highly recommend that you check if you meet the education and experience requirements before starting your application. If you do not have the 35 hours of formal training in project management, then you should take a PMP course to collect hours and also get on your way to prepare for the exam.
Our course will not just provide you the required hours but will also help you prepare for the exam.