iXPAND USB3 - unable to edit files

I can copy files to the excel app from ixpand drive. In iXpand drive app go to the folder where the excel file is and choose “Select” Then select the file you would like to open in excel and tap “More options” this will open the iOS share menu. Scroll over the the excel app and choose it to open the excel file. This will open the file as read only in the excel app. Once that is done you will have the option to copy the file to the iOS device and once that is done you can edit the file.