(Jon Kabat-Zinn, known for helping to increase the popularity of secular mindfulness in the West, defines mindfulness as "paying attention, in the present moment, non-judgmentally." I'll use that definition.)
Tough not to bump into the term "mindfulness" nowadays especially around those working in mental health or education (and I'm sure many other fields). What is the appeal? One possibility is that mindfulness is a tool for turning off or quieting a bit our internal editors, the voices in our brains that critique, analyze, judge ourselves and others. Those editors serve some good purposes, but they seem to steer toward worry and anxiety, possibly hard wired to do so after billions of years of evolution. In my own mindfulness practice and those of the much more experienced, mindfulness can often be helpful in reducing the power of that voice. If I'm having doubt, I find myself better able to interrupt that thought loop should I decide it makes sense to do so. And, turning off that doubt allows for getting back to the actual experience of life whatever that experience may be in the moment.
Try listening to the experts out there and their explanations of what mindfulness does for them. Some of the experts I've found incredibly insightful:
Dan Harris -https://youtu.be/ywp4vaFJASE
Sam Harris - https://youtu.be/qGIjJ1yohHs
Joseph Goldstein - https://youtu.be/unwBdzxJLUM
Sharon Salzberg - https://youtu.be/LML17BRZppU