To create a CSR, visit your my.wpengine.com User Portal and click the “SSL” link under the install in question.
There, you will click “Add Certificates”
On the next page, choose the option to “Start the process” under the “Import a new certificate” section
Then you will select the type of certificate you will be installing on your WordPress site: Standard (1 domain), Wild Card (1 domain, infinite sub-domains), or Multi-domain (up to 99 domains)
You will then be presented with the CSR that you can provide to your certificate issuer, to generate an SSL certificate
Once you have received the files from your certificate issuer, you will then Upload the Third-Party Certificates.