When you import an Illustrator file form the clipboard and paste this file as PDF in EasySIGN then EasySIGN will open automatically a new worksheet. This is to be able to maintain (in case available) the layer information.
We recommend you to use the compatibility feature as available within EasySIGN. In that case you can choose to export or open a file from Illustrator in EasySIGN. Read more about compatibility.