Go over the curriculum taught in the e-learning training. Choose what the most important parts of the training were and what you expect the employee to retain.
Choose a scoring method. If you are asking rating questions, then you will need a scale. If you are asking multiple-choice questions, it could be a percentage. If you are asking fill-in-the-blank or essay questions, you must determine if there is partial credit.
Let employees know whether this is a graded portion of the course or if it is just for your knowledge. Make it clear if the employees still have access to the material, whether or not you want them to answer the questions from memory without help from paperwork or computer or have it be a "closed-book test."
Send out the survey either at the end of the course online or via email. Make sure there is a deadline if you send it out via e-mail so you can tally the results.
Offer a section for comments from the employees. Find out if the overall feeling is good towards the e-learning course. Let students offer suggestions for improvement.
Score the overall results. You should have a score in mind that you expect the group to get as a whole to give yourself parameters for change or satisfaction.