How to Keep Your Emails Away from the Promotions Tab of Gmail
Moreover, even if your user does check their Promotions tab, your email will be lying in the midst of a plethora of other marketing emails. So, no matter how much of your effort goes into crafting engaging content for the readers, if your email gets buried in the Promotions tab, the chances of it being noticed are slim.
You can’t make changes to Google’s algorithms that work in the background to decide which email goes under which tab. However, you can make a few changes in your emails to make them recognized as primary emails.