Trackback in WordPress is a way for websites to communicate with each other by notifying other websites that they have linked to their content. When a website links to your content and has trackbacks enabled, WordPress automatically sends a notification to that website, letting them know that you have linked to their content.
Similarly, if you link to content on another website that has trackbacks enabled, WordPress will receive a notification from that website, letting you know that they have linked to your content.
Trackbacks are a way to create a network of interconnected content on the web. They can be helpful in promoting your content and building relationships with other websites in your niche.
By default, trackbacks are enabled in WordPress. If you prefer not to use this feature, you can disable it in the WordPress settings. If you choose to leave trackbacks enabled, you may receive notifications when other websites link to your content, and you can review those links to see if they are relevant to your website or content.