Need for Speed Unbound

This achievement is for completing 10 takeover events.

This one is pretty self explanatory. While the description doesn't specifically say it needs to be done in story mode, I don't believe there are takeovers currently available online. It's possible takeovers are added in a later update, but even if they are it's much easier to earn it in story mode. Because of that, this guide will focus on how to obtain it in story mode.

While you're progressing through story mode towards competing in The Grand, there are events every day and every night at the meetups throughout the game. For this achievement, only doing takeovers count. You can see which events are takeovers when you select a meetup to view its events and you see an event called "Takeover" with a yellow and black circle like you would see on a crash dummy, or when you enter the event and you see the pre-race cutscene of A$AP Rocky hyping up the crowd.

Simply complete 10 of these while playing story mode and you'll get your achievement. No need to worry about winning. You should earn this naturally while progressing through the main story, but if you somehow don't, you can still compete in events afterwards.