For any share you always have two levels of access/permission to configure:
1. At the share level (right-click->properties->sharing->permissions)
This configures whom can Read, Change or Full Control over the content of that share;
2. At the folder level (right-click->properties->secutiry)
This defines the level of access to the contents of that specific folder.
In general terms, this means that a user can have full control for a specific shared folder, but if at the share level it only have Read permissions, there will be no way of that user be able to create even just a text file.