If you mean Minecraft Pocket Edition, you tap and hold on the screen with food in your hand. Certain foods heal more than others.
Left trigger
You can only eat when you are low on hearts. Just press
When you have food in your hand press and hold down in an empty space.
You don't. They are purely to get ink sacs. They multiply naturally.
no
Carry the food and then right click.
Minecraft's bats do not eat anything. You can't feed them anything nor do they look for any other kind of food.
right click + hold
No, you can't.
Right-Click with the food in your hand.
Put food in your handHold down on the food that is in your hand