You can also go to the Draft WB, select all the lines in the treeview by clicking on first then holding shift key and clicking on last, then click on the Draft_to_Sketch icon in the Draft WB tool bar. That will put all the lines into a sketch, not constrained.
You can then Pad the object in Part Design by creating a Body, moving the sketch into it by drag and drop in treeview, then attach it to an axis plane of the body (presumably XY plane) then click on Pad and select the desired thickness, my example used 2mm.
The best method depends on your specific use case and the object you are trying to model.
This is just a quick example of what I suggest here.
and the file