Processing Toolbox > Scripts > Tools > Create new script

##Copy_features=name
##original_layer=vector
##Copy_to=vector

original_layer = processing.getObject(original_layer)
copy_to_layer = processing.getObject(Copy_to)

feats = [ feat for feat in original_layer.getFeatures() ]

Copy_to_data = copy_to_layer.dataProvider()
attr = original_layer.dataProvider().fields().toList()
Copy_to_data.addAttributes(attr)
copy_to_layer.updateFields()
Copy_to_data.addFeatures(feats)