There is no limitation on methods for undergraduate research, though that will depend on program and university. For social sciences, a good and free resource for quantitative methods is at https://www.socialresearchmethods.net/kb/index.php.

Methodology is a method for doing research.

From my point of view, there is no fixed methodology for doing under-graduate or post graduate research.

It depends on the types of study that you want to emphasize and needs to consider sample population and time interval.

It will depend on your research topic, scope and objective.