This option only appears on charts with multiple series of data, such as column charts that group multiple variables per period. Double-click the trend line to open the Trendline Options sidebar.

If you need to create a Line Chart and Scatter Plot in Excel, read through this article. We have also explained which one is right for you.

You can make a curved graph in Excel and Google Sheets using this tutorial. Learn how to convert sharp edges into smooth lines in a spreadsheet graph.