To customize and format table borders and shading in OneNote Online:

1. Choose a table style – from the Table Tools Design tab, click on the Table Styles or Shading options to choose a style and color for your table.
2. Customize table borders – in the Table Tools Design tab, select from the Border buttons to customize or remove borders from any side of the table.
3. Create a Better Display – adjust the background color, width, and height of cells and set a border style to separate cells and visually order your information.