Desktop
1. Right-click anywhere on the chart.
2. Select "Properties" to enter display settings.
3. Check the "Buy Price Line" option.
iOS:
1. Open the chart.
2. Click anywhere and select "Settings".
3. Check the "Buy Price Line" option.
Android:
1. Enter the settings menu.
2. Select "Chart".
3. Check the Bid Line option to enable it.