How do you lock a file in Microsoft Word?

This is done through the File Attribute control. You will need to change the Attributes of whatever files you wish to be locked by switching the files to Read-Only.

This can be done in a few ways. Right click on file and select properties. Check the read-only checkbox and then click apply and ok.

Or, you can do this through Command line and the syntax should be like below:

attr C:\urfile2blocked.xxx +R

.XXX = the application extension of the said file and +R applies the Read-Only to the file. If you want to unlock it do

attr C:\urfile2blocked.xxx -R