You need to understand that all the formatting available in other specialist programs like Excel may not necessariy display using exactly the same formatting in a html email. Plus if people use Plain Text then all formatting is stripped anyway, so you cannot guarrantee how the email will look for the recipient. Options: You could highlight the section in excel, right click select Copy. Then in Thunderbird new Write message. Right click in text area and select 'Paste'. But be aware of potential formatting issues. This is why emails have the facility to attach documents. So the recipient can read the data using the correct application and also be able to detach documents from emails and save separarely. So you could save the excel document and attach it to the email. When using simple tables to show data, it is best to create them using the one provided in Thunderbird via Insert > Table or Formatting Bar option. attach image: If you want to take a snapshot of the Excel page. Select the excel window to get focus and use the 'Alt' +'Prt scr' keys. Open eg: 'Paint' then Paste into 'Paint', then save as jpg. Then attach the saved image to the email. In new Write mesage: click on 'Attach' locate and select the jpg image and click on 'Open',