Click inside the document
Go to Format
Select Bullets and numbering
Choose List options
Select None
If the paragraph index is in a numbered list, click the Numbered list button to turn it off
If the index is in the left margin, go to Tools
Select Preferences
Turn off automatic substitution options related to numbering if needed
If the index is in a table or outline, remove the list formatting from the affected paragraphs
Use Ctrl+Shift+7 on Windows or Cmd+Shift+7 on Mac to toggle numbering off