I got two confirmation e-mails about my online exam: one on the date I scheduled the exam and the other one 3 days before the exam date.
I checked my e-mails and they came from Pearson VUE, not directly from PMI.
Training for Project Management Professional (PMP)®, PMI Agile Certified Practitioner (PMI-ACP)®, and Certified Associate in Project Management (CAPM)®