1. Select the file(s) you need to compress. Then right click the selection and choose "7-Zip" -> "Add to archive..." from the menu.
The image illustrate how to compress file(s)


2. Make sure to choose "zip" for the archive format. Then enter your password (We highly recommend to set password with more than 8 characters which consists of alphabets and numbers), and choose the "Encryption method" you prefer. Then click "OK".

The image illustrate how to set the password to the archive file


3.Now the file is encrypted with password. To open the file, you will need to provide the password.


The image illustrate the prompt for password to de-crypt the file