political participation can be both formal/traditional participation such as voting or informal such as protesting, demonstrating or petition-signing or even volunteering.

Look up guides on how to build a questionnaire. It is a long question to answer here but to keep in short: make sure that your questions do not content any bias, and have mainly close questions (with enough different response options) and some open ones to let them add illustration of their experience. good luck!

You should take into consideration not only student participation in national, regional, and municipal governments, but student government political participation as well. Many universities have democratic student governments that represent the interests of students, and there are often smaller student governments for each faculty or department. Similarly, there are political clubs and societies that also have elected executives. In terms of activism at student government levels, student newspapers and social media would be good outlets to look for student perspectives.