Add a Web part section is not showing in Internet Explorer for the Intranet sites.
To overcome this issue for the sharepoint intranet sites we need to set this site as to be open in compatibility mode. To do that follow the steps as given below.
- Go to Tool > Compatibility view settings
- Add the url of your site in the text box and then click Add.
- Check the box of Display intranet sites in compatibility mode
- Click close.
Let me know in comments if this helps or not.