Updating the dictionary by a user

For example if the user has to choose an item from a droplist when entering the form, and what they want to enter does not exist. Can he add a new element to the dictionary from his form?
I would like to load the list of MA applicants already registered in Cameroon to reduce time and entry errors.

Yes, It is possible to expand the dictionary as needed. (check this out: Dictionaries - Configuration )
You can get the MA applicants by adding a new dictionary, make sure you use the right URL with the appropriate value for “class”.
This should help.