Assume that your text box has an ID eg: app_title, you can hover over it using

    element = @driver.find_element(:id,"app_title")
    @driver.action.move_to(element).perform

This will place the mouse focus on the textbox and you will see your edit icon on the screen. After that it is simple, you can click on it using

@driver.find_element(how,what).click

Assume that your text box has an ID eg: app_title, you can hover over it using

    element = @driver.find_element(:id,"app_title")
    @driver.action.move_to(element).perform

This will place the mouse focus on the textbox and you will see your edit icon on the screen. After that it is simple, you can click on it using

    @driver.find_element(how,what).click