Issue:
Add a Web part section is not showing in Internet Explorer for the Intranet sites.
Resolution :
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.
Happy SharePointing!!!