There are two types of certificates, single and complete.
A single certificate can be generated for one module and it shows the result based on the single test that was taken.
Go to Your skills > Test results
Click on Certificate
Go to Reports > View a driver > Test results.
Click on Certificate next to the result you want to create the certificate for.
Go to Reports > Drivers and courses > Manage drivers.
The certificate button will appear green and will be activated if the driver has completed all modules.
This creates a certificate that contains the best result from every module that the driver has registered a score for. For example, if a driver has taken the Emergencies module twice, scoring 88% and 100%, the certificate will only show it once with a score of 100%.