In most organizations, training has become a routine, perfunctory assignment for the HR Department. Training for employees is not conducted seriously. In the first instance, apart from the recommendation of an employee's immediate superior, there should be simple tests (many of them available on the internet) to assess the true shortcomings or grey areas of an employee who needs a particular type of training.
In many organizations, the same immediate superior who recommends training for their team member will also prevent them from attending training, using the excuse of pending work or a shortfall that does not allow them to be spared. In an HOD meeting, the same person may say, "My team members are not sent for training!"
Firstly, develop the habit of communicating all these nominations, cancellations, etc., through email only and keep saving those emails for future reference and compilation in your report.
Your report can be prepared in a simple Excel sheet, which should contain, among other things, information on employee details and their nomination for training, when the communication was sent, whether the employee attended the training, and if not, the reason for it.
If you track this information diligently, capturing it and submitting it to your Head, the statistics will demonstrate your involvement and commitment.
If my understanding of your post is correct, then the above is my response!