18. The document editing method according to claim 15 , wherein the processor determines a superimposition area of the extracted object and an object hierarchically higher than the extracted object; and wherein the processor converts information included in the superimposition area of the extracted object into the different information.
15. A document editing method executed by a document editing apparatus for editing an electronic document including a plurality of hierarchically arranged objects, the document editing apparatus including a storage and a processor, the document editing method comprising: extracting an object from an original electronic document stored in the storage, the original electronic document including the hierarchically arranged objects representing one of a text, an image, a drawing, and a table; determining, by the processor, whether the extracted object is superimposed by a user specified area serving as a masking area of a target document input by a user; converting, into different information, information included in an area of the object determined to be superimposed by the user specified area to generate a processed electronic document; and storing the processed electronic document in the storage.