Once you've added a food entry to My Daily Log, you have a few options for working with that entry.
You can open it to view details, edit it, copy it to another day, or delete it.
Access each of these options by tapping the More Options (⋮) button to the right of the entry.
Then, select your desired action from the menu.
The View option lets you view the details for the given log entry, including nutritional information, serving units and portion size, meal time (breakfast/lunch/dinner etc) and more.
The Edit option opens in a similar window to what you'll see with View, but offers the ability to modify the nutritional information, serving units and portion size, meal time etc.
The Copy To option will present you with a date selector. Choose a date from the calendar shown, and select Set, and the food log entry will be copied to the chosen date.
The Delete option is described in a separate article, but essentially does what it says; it let's you completely delete the selected food log entry from My Daily Log.