Most whole chickens that you buy in stores do have giblets in them.
If the chicken has giblets you need to remove the giblets before cooking the chicken.
If the whole chicken does have giblets the giblets will usually be in a cavity of the chicken and in a plastic bag and it needs removed before you cook the chicken.
Turkeys also usually have giblets in them as well that need removed.
You usually use the chicken or turkey giblets to make turkey or chicken gravy.
You can however just make the gravy without the giblets which is what I do as I don't like using the giblets.
My cat likes the chicken and turkey giblets though so I give the giblets to him.