A Certificate Signing Request (CSR) is required in case you wish to obtain an SSL certificate which will encode all the payment and login details that are exchanged between your website and its visitors. The CSR contains information about the site and its owner in Base64-encoded form - website address, physical address plus email, company name and unit, and the like. Based on this code, an authorized SSL vendor provides you with the certificate, that is digitally signed with the vendor's private key so as to identify that they are a trusted issuer. At the time of the CSR generation, a unique private key is also created and the installation of the SSL involves all four codes - both the keys, the certificate and the CSR. After that, you'll be able to use a URL that begins with https:// for your website instead of http:// and the website visitors can view the info that you have provided for the CSR using their Internet browsers.