[Solved]-Change type of points of highchart's scatter chart-Highcharts

You should add marker property inside each serie with symbol: 'circle' like this:

 this.chartOptions = {
      plotOptions: {
        scatter: {
          lineWidth: 2
        }
      },
      yAxis: {
        min: 0,
        title: {
          text: ''
        }
      },
      series: [
        {
          type: 'scatter',
          data: [...],
          marker: {
            symbol: 'circle'
          }
        }, {
          type: 'scatter',
          data: [...],
          marker: {
            symbol: 'circle'
          }
        }, {
          type: 'scatter',
          data: [...],
          marker: {
            symbol: 'circle'
          }
        },
      ]
    };