Much depends on local procedures. Airfield within a Class D will usually have entry/exit lanes, typically (though not always) aligned with VRPs, meaning you will need to request a VFR arrival via that entry lane. Usually done when in contact with Approach/Radar, once entered into the zone you are handed to tower.
If it's OCAS but controlled then you would call the tower, request airfield information and joining instructions.
If uncontrolled you just request airfield information and state your intentions.
If there's an ATIS it's worth listening to that first before you call Approach, that way you can say you have information x.
Smithy