Mailbird Star feature lets you mark your most important emails, and be able to always bring them up when you need them. Here's how you can do it.
1. Right click and select Mark as starred
2. Hover to the sender profile picture and select the start feature
How you use it is up to you. To keep a list of your best emails. As a to-do list. To mark emails from important people.
Whatever you use it for, Mailbird makes it super simple.