1. Open the MT4 platform and go to the "Market Watch" window. If the window is not visible, you can access it from the "View" menu or by pressing Ctrl+M on your keyboard.
2. Right-click anywhere in the "Market Watch" window and select "Show All" from the context menu. This will display all available instruments.
3. Right-click on any instrument and select "Symbols" from the context menu.
4. In the "Symbols" window, select the instrument for which you want to display the ask price and click on the "Properties" button.
5. In the "Symbol Properties" window, go to the "Common" tab.
6. In the "Common" tab, make sure that the "Show Ask Line" option is checked.
7. Click on "OK" to save your changes and close the window.