Add parameters to URLs to identify campaigns that refer traffic.
To take full advantage of Google Analytics reporting, we suggest you use UTM parameters when sending out email blasts or sharing links on Facebook, Twitter, Instagram, or any social media.
By adding campaign parameters to the URLs you are using in your ad campaigns, you can collect information about the overall efficacy of those campaigns and understand where the campaigns are most effective. Please refer to the Custom campaigns guide from Google to learn how to use UTM tags in your campaign.
The resulting URLs can look like this for your email blast
and this for posting on Facebook