Main Settings / General Settings / Student Form/ Default Values / Enable auto-generation of the Student Academic Registration Number
Here you can enable automated academic registration numbering when a new student is created by the secretariat.
Example
Setting -> Active -> Auto (Figure 1 , Figure 2)
Figure 1
Academic Registration Number field is disable because is auto generated (Figure 2)
Figure 2
Setting -> Active -> Manual (Figure 3)
Now its enabled and you can write your number
Figure 3