You can use 7-zip to encrypt a file for sending via email:
1. Save the file “My File” to your desktop
2. Right click the file, select 7-Zip | Add to Archive | Enter password in “Enter Password” box
3. Click OK, then attach the file to an email.
The person on the other end will need 7-Zip a readily available free program. I recommend sending the password via text, fax or phone.
If you frequently send confidential emails, Gpg4win / GpgOL is an efficient and effective solution to secure your email messages.