The short answer to this question is both.
The experience of emotions is a normal part of the human experience. For a variety of reasons many of us may not have a lot of experience and knowledge about emotions. For example, in my background, I had trouble identifying emotions and knowing how to handle them.
Mindfulness meditation offers an opportunity to get to know the experience of emotions when they appear. After gaining more experience in a formal mindfulness practice, one can then use some of the same strategies in everyday life.
In a formal mindfulness practice, when emotions surface and they are strong, the emotion itself can become the object of the meditation. It is helpful to first identify the emotion as best you can and bring an attitude of acceptance to the experience. Is is also helpful to explore the experience of the emotion including body sensations, thoughts, and anything else in our experience that we sense makes up the experience of an emotion. Mindful meditation doesn’t eliminate emotions, but, shows us that they temporary and impermanent.