It depends on the type of certificate you are using.

We have free SSL certificates available to all Kinsta customers provided by our Cloudflare integration. These SSL certificates do not require a CSR or key to install on your WordPress site.

If you’re purchasing your own custom SSL certificate, you’ll need the server type, CSR code, and RSA key. For more details, please see our guide on how to add an SSL certificate and what to select for each value.