[Vuejs]-How to change fontSize for dataLabels?

You can find a pretty good summary of your options here on this page: https://apexcharts.com/docs/options/datalabels/

style: {
      fontSize: '14px',
      fontFamily: 'Helvetica, Arial, sans-serif',
      fontWeight: 'bold',
      colors: undefined
  },

You can simply provide styling in CSS class.

  .apexcharts-pie-label{
    font-size:25px;
    }