This is known as "retargeting", which works by showing targeted ads to the users who visited your website and didn't purchase a product, fill in a contact form, download a file, sign up to your newsletter or any other form of conversion.
Retargeting ads entice past visitors to return to your website by showing them relevant ads as they browse the web and use various apps. This helps to keep your brand and products at the forefront of past visitors' minds.
