Impressions and Reach
Reach is the total number of people who see your content. It’s the amount of unique people who see your content. Impressions are the number of times your content is displayed, no matter if it was clicked or not. Impressions can mean one user has seen your content multiple times and hence are not unique.
An impression means that content was delivered to someone's feed. A viewer doesn't have to engage with the post in order for it to count as an impression
This is how popular social media advertising platforms, such as Facebook, Instagram, and Linkedin, analyze your ads’ performance. Increasing impressions isn’t necessary good for conversions and reach can even be harmful when you’re trying to target a niche audience.