Help > Authoring > Using Markup > Inserting Files > Inserting an Existing File
  
Inserting an Existing File
You can insert an existing complete or partial file in an already-open document.
To insert a file:
1. Position the cursor in the target document.
2. Choose Insert > File.
3. In the Insert File dialog box, choose a filename from the File Name list or enter a path name in the text box.
Note that you can choose the desired file extension from the Files of Type field to specify both the file types listed and the format in which they will be read into the target file. Parsers will be invoked automatically, based on the file type selected.
4. Click OK.
Some existing files may be reused several times, and these files may be defined as file entities.
If you know that your source file contains elements not in your DTD, turn off context checking before inserting the document, fix the incorrect markup, then use Tools > Check Completeness to verify that the document now conforms to the current DTD.