For Form Six Applicants (NECTA) use your Form 4 Index Number. The format for Form 4 Index Number is S0332/0012/2009 i.e. centre_no/candidate_no/year.
For RPL applicants use the RPLNumber given to you when you registered. The RPLNumber format is RPL/2015/0034 i.e. RPL/year/serialno
If you did your exams outside Tanzania, provide the examination number as seen on your certificate i.e. Exam_no/year. However, you must first go to NECTA to validate your certificate and present a letter of proof to TCU.