A record can be duplicated in the field directly from your mobile device. Any record can be duplicated by long pressing, press and hold, on the record from the list view, then selecting the duplicate option in the picklist that displays.
When duplicating a record you have three options: To duplicate the record’s entered in data values and location, to duplicate the entered in data values only, or to duplicate the location only.
There is no way to copy media to a duplicated record. If you wish to copy any media files over, it will have to be done manually after the record has been duplicated.