If you enable this option, the amount collected for registration fee can be adjusted to any other fee type. Follow the below path to enable the setting

Settings --> Admissions --> Branch Admission Settings --> Select the Branch --> Select the radio button against the "Is Registration Fee to be adjusted in Tuition Fee? " --> Save

After enabling this setting, follow the below path to add the fee types for which the registration fee to be adjusted

Settings --> Admissions --> Registration Fee Adjustment to Fee Type --> Add