Hello Imran,
Please follow the below steps to provide the Certificate Request to CA -
1. Click on Create Certificate Request. It opens the CSR in new Window.
2. Click on Save Local file to save the CSR.
3. Send this generated file to SAP for CA signing or any other third parties like DigiCert.
4. Once you get the Signed Certificate from CA, click on import response to upload the Response certificates.
To get it CA signed from SAP, you can follow the below link -
SSL Server Certificates | SAP Support Portal
Sending the Certificate Requests to a CA - Network and Transport Layer Security - SAP Library
Regards,
Nitin Deshpande