Hello ashutoshs,
Thanks for contacting us with your question!
Q1: If you have two separate charts and you want to add some text between them you can just add a proper HTML tag with text between them. Just like in this demo:
https://jsfiddle.net/BlackLabel/dbuL5ewt/
Q2: To create a label you can use a
Highcharts SVGRenderer. You can set it properly using x and y values and it is scrollable along with the chart.
Demo: https://jsfiddle.net/BlackLabel/z7u9qbtj/
API Reference: https://api.highcharts.com/class-refere ... VGRenderer
https://api.highcharts.com/highcharts/c ... lePlotArea
Feel free to ask any further questions!
Regards!