|When it comes to encrypted email, it always takes two to tango.|
The simplest way is to put the information in a file, such as a Microsoft Word or PDF file, and encrypt with a password. Nearly everyone in business has Microsoft Word and Adobe Reader, so can decrypt the password. But the other party must be willing to let you submit the password to them in a secure way. If you email and ask how to provide the password, and they ignore you, you can't send a file securely.
Some of the methods mentioned in the link provided by Clem/CA require the other party to install software on their computer. In a corporate environment, that's a non-starter. Usually most employees won't have administrator access and won't be able to install anything. Those who do have administrator access will probably refuse to install anything.