Impressions do not measure clicks, comments, or other interactions your audience may have with your content or advertisement. However, impressions can help you understand if your ad is raising awareness for your brand, product, or service.
When using Google Ads, impressions can help you determine how relevant your ad is. If your ad pops up on screen a lot when users search for your keywords, then you know your ad is relevant.
While impressions tell you how many people have seen your content, reach tells you how many people actually interacted with it. In order to improve your engagement rates, you need to look at both your reach and the number of impressions you have.
Many social platforms include an analytics tab that can monitor the number of impressions your content has. Google analytics is another platform that can help you see how your content is performing.