On January 13, 2020 the FAA implemented changes to how the written tests are scheduled and accomplished. This change caused some confusion for those who were trying to schedule tests around that date, but hopefully the system will become more clear over time.
The instructions provided on the PSI Website are generally the most complete and understandable I have found. Go there for more details. You can also find testing center locations, and do practice tests on that site. It is a great resource.
The basic changes are:
First you need to create an account in IACRA, and obtain a FAA Tracking Number (FTN). The FTN will be required for scheduling the test. Your FTN will remain the same for all future FAA tests, so you will only have to do this once.
Create an account on the PSI website, and schedule your written test.
Additional FAA reference material regarding IACRA and written testing is found here and here.
As with anything aviation-related, testing requires a certain amount of paperwork. Here is a list of the minimum paperwork required to be presented to the examiner before testing begins.
A Government-issued photo ID must be presented to the examiner. For International applicants, this document must be a valid passport.
Two original completed copies of FAA form 8610-2. If applying based on civilian or military experience, these must be signed by an FAA Inspector.
Graduation certificates for applicants testing on the basis of Part 147 training.
Current (less than 24 months old) written test results for applicable ratings.
A completed “Pilot’s Bill of Rights” (may be provided by the examiner).
If previously failed, the previous 8610-2 form(s) must be presented. If the failure was within the last 30 days, a retraining certification signed by a certified mechanic must be included as well.
Current mechanic certificate (if the applicant already holds a certificate with one rating).
Payment, as agreed-upon by the examiner.
Failure to provide these documents will likely result in delay or cancellation of the test. Other documents may be additionally required, depending on the applicant’s exact circumstances. When in doubt, contact your examiner.