First: it's not actually needed to use them. If all the users need to be active from 3-12-2020 until 3-12-2023 as in your screenshot, the best course of action is
- option 1) setting those dates as the course start or end date
- option 2) setting the course as unaccessible 1095 days after the first access (days of validity).
Active from - Active until fields can be used to allow specific users to enter the course only from a specific date and only until a specific date.
Dates can be edited user by user or in bulk.