The phrase "important pillar" refers to something or someone that is significant, essential, or crucial. It represents a strong support or foundation on which something relies or depends upon. Full definition
As in many other countries, religion is the most important pillar of society, which controls education and culture. (globaleducationmagazine.com)
In fact, they are the most important pillar of the medical billing process. (coverlettersandresume.com)
As a data analyst or technical support professional, you education will provide essential information to your reviewers and will serve as a very important pillar of your application. (livecareer.com)