1. In OneNote's top bar, select Insert.
2. In the grey tool bar below, under the Files section, select Spreadsheet. (For Windows 10: select "Insert File Attachment" -- no need to follow any further instructions)
3. From here you may select a new or existing Excel document.
4. Once inserted, you may edit the shown data by hovering over the created spreadsheet then selecting Edit in the upper-left corner of the sheet.
5. Example:
    
   
   
   
   
   

Adding you own tags for easier searching:

As more and more pages get added, it may become a little difficult to find the exact page you're looking for. This may be avoided by adding tags to keep things in order. OneNote also comes with its own tags, which you can freely use and cover most topics and categories as you may need them.

1. Navigate to the Home section.
2. In the Tags portion, select the Find Tags button.
3. At the bottom of the new gray column, select Customize Tags.
4. A window should pop up that looks like this:
   
   
   
   
5. Select New Tag, and modify the tag as you choose by adding different text colors or icons.
6. Upon finishing customizing your new custom tag, close out of the Customize Tags window.
7. On the page you wish to tag, under the Tags portion again, scroll through the window on the left and select the Tag you wish to use on the page.
   
   Note: Custom tags are saved to the device being used, and you cannot readily share custom tags you've made with others. They may need to recreate the tag in their own OneNote online or desktop app in order to use a custom tag.
   
   
   

Other Resources:
Check other related articles at the OneDrive and OneNote Home page.