Can I purchase SSL from any other company and install it on my HostingWebsitez account?

Yes, you can purchase SSL from any company you like. For purchasing SSL, CSR (Certificate Signing Request) is required. Installation of SSL certificate requires SSL Private Key. If the CSR has been generated on the Jaguar server then you don’t need to provide the SSL Private Key but if the CSR has not been generated at Jaguar server then you have to provide the SSL Private Key associated with the SSL certificate so that the SSL certificate can be installed.