Default settings for groups to be expanded or collapsed
To access this functionality, first open a board. Then click on the gear icon near the top right corner. This will open a menu as shown in the screenshot below. Select the option that you prefer from the drop down box inside this menu. The setting will be saved automatically.
This setting is specific to each individual user. The setting one user chooses will not affect how other users open that same board. No special permission is required to use this feature.