I need to understand if Alfresco (we are using the trial last version) allows the implementation of dynamic picklist populated with external data (from excel sheet or csv or database) into Share UI interface or this is only possible through a custom interface.
For example: I want to manage contract documents and for each contract the possibility to select the supplier of that contract from a picklist that is periodically populated with external data (suppliers can change over time). I know that this is possibile with a custom interface, my question is whether it is possible to do it directly in Alfresco Share.
Yes, you can configure properties on the document details page to populate a dropdown from any data source, be that a data list or some other service.
The add-on referenced uses data lists to manage the possible values and then those values are used to populate dropdowns in any Share form.
You can also write your own Java classes to do this if you want.
This is not difficult to do but it will not be out-of-the-box unless one of the add-ons meets your requirements.