Hi Jenya,
Yes, a user can upload a csv to update specific columns. A system admin would have to setup the file import and then publish the action or process to the dashboard for an end user. Then the end user can click on that action or process button and Anaplan will prompt the user for an upload file. The file used to create the action and the file uploaded by the end user will have to have the same column headers and data formats.
Thank you,
Vicky