The Video above explains how to use the Frequency Formula of MS Excel. The Text below is from a Microsoft Excel Support BlogPassword Protect A Excel File
Password protect documents, workbooks, and presentations
CAUTION: Keep your password in a safe place. If you lose or forget the password, it can’t be recovered.
What do you want to do?
- Set a password in a Word document
- Remove password protection from a Word document
- Set a password to modify a Word document
- Set a password in an Excel spreadsheet
- Remove password protection from an Excel spreadsheet
- Set a password to modify an Excel spreadsheet
- Set a password for a PowerPoint presentation
- Remove password protection from a PowerPoint presentation
- Set a password to modify a PowerPoint presentation
Set a password in a Word document
To encrypt your file and set a password to open it:
- Click the Microsoft Office Button
, point to Prepare, and then click Encrypt Document.
- In the Encrypt Document dialog box, in the Password box, type a password, and then click OK.
CAUTION: Keep your password in a safe place. If you lose or forget the password, it can’t be recovered.
You can type up to 255 characters. By default, this feature uses AES 128-bit advanced encryption. Encryption is a standard method used to help make your file more secure.
- In the Confirm Password dialog box, in the Reenter password box, type the password again, and then click OK.
- To save the password, save the file.
Remove password protection from a Word document
- Use the password to open the document.
- Click the Microsoft Office Button
, point to Prepare, and then click Encrypt Document.
- In the Encrypt Document dialog box, in the Password box, delete the encrypted password, and then click OK.
- Save the file.
Set a password to modify a Word document
In addition to setting a password to open a Word document, you can set a password to allow others to modify the document.
- Click the Microsoft Office Button
, click Save As, and on the bottom of the Save As dialog, click Tools.
- On the Tools menu, click General Options. The General Options dialog opens.
- Under File sharing options for this document, in the Password to modify box, type a password.
- In the Confirm Password dialog, re-type the password. Click OK.
- Click Save.
NOTE: To remove the password, repeat these instructions and then delete the password from the Password to modify box. Click Save.
Set a password in an Excel spreadsheet
To encrypt your workbook and set a password to open it:
- Click the Microsoft Office Button
, point to Prepare, and then click Encrypt Document.
- In the Password box, type a password, and then click OK.You can type up to 255 characters. By default, this feature uses AES 128-bit advanced encryption. Encryption is a standard method used to help make your file more secure.
- In the Reenter password box, type the password again, and then click OK.
- To save the password, save the file.
Remove password protection from an Excel spreadsheet
- Use the password to open the spreadsheet.
- Click the Microsoft Office Button
, point to Prepare, and then click Encrypt Document.
- In the Encrypt Document dialog box, in the Password box, delete the encrypted password, and then click OK.
- Save the spreadsheet.
Set a password to modify an Excel spreadsheet
In addition to setting a password to open an Excel spreadsheet, you can set a password to allow others to modify the spreadsheet.
- Click the Microsoft Office Button
, click Save As, and on the bottom of the Save As dialog, click Tools.
- On the Tools menu, click General Options. The General Options dialog opens.
- Under File sharing, in the Password to modify box, type a password.
- In the Confirm Password dialog, re-type the password. Click OK.
- Click Save.
NOTE: To remove the password, repeat these instructions and then delete the password from the Password to modify box. Click Save.
Set a password for a PowerPoint presentation
To encrypt your presentation and set a password to open it:
- Click the Microsoft Office Button
, point to Prepare, and then click Encrypt Document.
CAUTION: Keep your password in a safe place. If you lose or forget the password, it can’t be recovered.
- In the Password box, type a password, and then click OK.You can type up to 255 characters. By default, this feature uses AES 128-bit advanced encryption. Encryption is a standard method used to help make your file more secure.
- In the Reenter password box, type the password again, and then click OK.
- To save the password, save the file.
Remove password protection from a PowerPoint presentation
- Use the password to open the presentation.
- Click the Microsoft Office Button
, point to Prepare, and then click Encrypt Document.
- In the Encrypt Document dialog box, in the Password box, delete the encrypted password, and then click OK.
- Save the presentation.
Set a password to modify a PowerPoint presentation
In addition to setting a password to open a PowerPoint presentation, you can set a password to allow others to modify the presentation.
- Click the Microsoft Office Button
, click Save As, and on the bottom of the Save As dialog, click Tools.
- On the Tools menu, click General Options. The General Options dialog opens.
- Under File sharing settings for this document, in the Password to modify box, type a password.
- In the Confirm Password dialog, re-type the password. Click OK.
- Click Save.
NOTE: To remove the password, repeat these instructions and then delete the password from the Password to modify box. Click Save.