Protect Document is a very helpful tool to help you keep your file the way you left it. Edraw Office Viewer Component can protect word and excel document from modification by the end users. Only call the ProtectDoc method in the DocumentOpened event.

boolean ProtectDoc(long ProtectType, [in, optional] VARIANT Password);

Helps to protect the specified document from changes. When a document is protected, users can make only limited changes, such as adding annotations, making revisions, or completing a form.
ProtectType: The protection type for the specified document. WdProtectionType.
Password: Optional Object. The password required to remove protection from the specified document.

For Excel:

typedef enum XlProtectType
{
XlProtectTypeNormal = 0x00000001,
XlProtectTypeWindow = 0x00000002,
XlProtectTypeStruct = 0x00000004,
XlProtectTypeDrawingObjects = 0x00000010,
XlProtectTypeContents = 0x00000020,
XlProtectTypeScenarios = 0x00000040,
XlProtectTypeUserInterfaceOnly = 0x00000080,
}XlProtectType;

Example
The following vb script shows how to protect a document for only revisions.
Sub ProtectDoc_Example()
EDOffice.ProtectDoc XlProtectTypeNormal|XlProtectTypeWindow|XlProtectTypeStruct
End Sub

For Word:
enum WdProtectType
{
wdAllowOnlyRevisions = 0,
wdAllowOnlyComments = 1,
wdAllowOnlyFormFields = 2,
wdAllowOnlyReading = 3,
wdNoProtection = -1,
}WdProtectType;
Example
The following vb script shows how to protect a document for only revisions.
Sub ProtectDoc_Example()
EDOffice.ProtectDoc 0
End Sub

The above program code is same with the follow setting in the MS Word.

To enable Protect Document:

1. Click on Tools in the menu bar
2. Then click on Protect Document…
3. Then a window will pop-up asking you what you want to protect your document for.
-The Tracked Changes option allows you to track every single change that was made. It changes the color of the text to red and gets underlined if you make any changes
-The Comments options only allows the user to put in comments. (To insert a comment go to Insert>Comment and to view a comment go to View>Comments)
-The Forms option only allows you to edit forms in the document. You can’t edit anything else
4. To choose your option just click on the choice that you want.
5. If you want a password then type in a password in the “Password (optional):” text box. (Word will ask you the password when you want to unlock your document!)
6. Click on OK
7. If you didn’t choose a password then Word will now protect your document. If you did then another box will pop up asking you to Confirm your password. Then click on OK.

Your document is now safe and protected!

If you want to unlock it then

1. Click on Tools
2. Then click on Unprotect Document
3. If you have a password then type it in the box that appears

Note: Word will protect your document until you Unprotect it. And the password is for one time use, the next time you click on protect document you need to type the password again.