Do you have files of a sensitive nature such as a word document with your bank details? It is easy to apply a password and secure any Microsoft Office document using these easy steps. These instructions are intended for Apple Macintosh users - PC users should use the Guardian newspaper's link in my links section (although the protocol is very similar to Mac).

There are a few issues to consider before applying a password to a document. The most important are:

• a method for remembering the password
• if you are sharing the document with other people, a way by which you can inform them of the password. This could be by electronic attachment, e mail, phone or by post! You could even give them a clue that you know they can answer.

it is still possible for hackers to access the password - the Microsoft protection is not as thorough as a firewall, for example. However, it does prevent somebody from quickly reading through your document, particularly in a work environment (although they might have time to e mail it and decrypt it later).

Microsoft Word for Macintosh 2004 version

Create or open your Word document. From the File menu "Save as..." and give your document a different name (one different character is enough...you can revert later). You can use the same name but Saving As allows you to experiment and make mistakes - you can delete the file later.

Before clicking the "Save" button, click the "Options" button at the bottom left of the window.

From the left-hand list click "Security".

This produces a dialogue box where you will enter your passwords.

Enter your chosen password(s); remember that letters are case sensitive and you should also include some numbers

You may complete either or both boxes; if the latter, both passwords may be the same. "Password to open" results in a dialogue box whenever anybody (including yourself) opens the document. "Password to modify" means than anybody making alterations to the document needs this password - I will explain this in a moment.

Click the "OK" button.

A dialogue box entitled "Confirm Password" appears; re-enter your password and click "OK".

The same dialogue box to appears, this time inviting you to "Reenter password".

Re-enter your password and click "OK" for a second time!

You now return to the "Save As" dialogue box. Here you have two choices with your file name:

• Modify the file name (strongly recommended, in case you make an error)
• Use the same file name. This prompts the usual dialogue box:

"An item named FILE NAME.doc already exists in this location. Do you want to replace it with the one you are saving?"

Click the "Replace" button if you're sure.

And that's it - next time you Open your Word file, it will prompt you (or anybody else) for your document's password.

There are many occasions when you do not need the document password-protected, but don't want people to alter as it is forwarded and read by various people. When somebody opens a "Password to modify" document, the following options appear (see picture):

"DOC NAME" is reserved by YOUR NAME. Enter password to modify, or open read only."

The "Read only" button is on the bottom left of the box.

This is a powerful and most useful tool.

Tools > Protect Document... explanation

You may have noticed a dialogue button called "Protect Document..." on the "Security" window. It is also possible to access this from the Tools pull down menu in Word - you are looking for "Protect Document..." (almost halfway down the list).

This results in a dialogue box which states "Protect document for..." with options "Tracked changes", "Comments" and "Forms". Thus, each successive reader of the document can add his/her changes, comments etc, but only password holders can see them. This level of security is independent to password protecting the document.

The password protection works along the same principles as those for Word. Follow this procedure;

From your File menu select "Save As..."

Click the "Options" button at the bottom left hand side

From the resulting dialogue box called "Save Options", enter your preferred password for

• Password to Open
• Password to Modify

Enter your chosen password(s) and click "OK".

Like the protocol for Word documents, you can have additional protection for Excel document changes and modifications. From the Tools pull down menu, choose "Protection" from where you can opt to protect the sheet, workbook or tracked changes.

Microsoft PowerPoint for Macintosh 2004 - no password protection

Curiously, PowerPoint 2004 has no password protection whatsoever. This is somewhat mysterious - arguably it is your beautifully-integrated and illustrated slides that need to be protected from some office lowlife competitor from stealing and presenting to the boss as his/her work!

Additionally, you can't open a PowerPoint presentation that has password protection and have to request the sender to remove it.

I do not know if Microsoft have included it in the latest Office for Macintosh 2008.

The vast majority of documents need no password protection but there may be a few that require extra security. Adding such cover allows you peace of mind - as long as you control these passwords sensibly!