Removing Legend from Line Chart

Hi, JackData 

If your desktop version is low, you can update it. 

Download Microsoft Power BI Desktop from Official Microsoft Download Center

If you use the latest version desktop, you can open file>>options and settings>>global>>preview features>>new format pane.

like this:

Before:

After:

New format pane details:

https://docs.microsoft.com/en-us/power-bi/fundamentals/desktop-format-pane 

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Best Regards,
Community Support Team _ Janey