An intermediate certificate will be emailed to you along with your SSL certificate. You can also download the intermediate certificate from the vendor's website, which is something that can be done if you didn't receive the intermediate via email. This is also sometimes referred to as the "CA Bundle." It is also important to note that some certificates have multiple intermediate certificates.
Below are the links that you can use to download your intermediate certificate from the vendor website:
- https://knowledge.verisign.com/support/ssl-certificates-support/index?page=content&id=AR657
- https://knowledge.geotrust.com/support/knowledge-base/index?page=content&id=AR1421
- https://search.thawte.com/support/ssl-digital-certificates/index?page=content&id=AR1384
- https://knowledge.rapidssl.com/support/ssl-certificate-support/index?page=content&id=AR1548
- https://support.comodo.com/index.php?/Default/Knowledgebase/List/Index/108/sha-2
