Created A Power Query table. I want to link a table to it allowing users to add customs lines

Lotam12 

You can only update the source file that the power query is pointing to get the data from.

If you're going to allow your users to access the source file to update it, then there needs to be an auditor/reviewer before the update can be done.  Ideally the query should be from a folder thereby the power query will just combine the updates dropped into that folder without modifying the existing sources that way if there were errors in the recent update all you have to do is pull that particular errant csv file so it can be corrected and dropped back into the folder when the error has been resolved, so your users can copy the lines from the query, put it on their excel update then save it as a csv file and drop their update into the folder.  you must also institute a file naming convention to identify who created the update and when the file was created.