Here i have described about the cranial nerves their function and their supply to respective structures.
1. Olfactory Nerve: It is a type of sensory nerve,

Supply:
It supplies to the Olfactory Epithelium(cells)
Function: Perception of smell from the nasal cavity.
2. Optic Nerve: It is a type of sensory nerve,
Supply: Retina (ganglion cells)
Function: Vision of retina.
3. Oculomotor Nerve: It i a type of motor nerve,
Supply: Midbrain, presynaptic midbrain, postsynaptic ciliary ganglion
Function: Motor function to superior rectus and inferior rectus,
medial rectus, inferior oblique, and levator palpebrae superioris
muscles, raises superior eyelid and also turns eyeball superiorly,
inferiorly and medially, constricts pupil and accomidates lens of eye.
4. Trochlear Nerve: It is a type of motor nerve,
Supply: Midbrain
Function: to the superior oblique muscle that assists in turning of the eye inferio laterally.
5. Trigeminal Nerve: It has 3 branches:
i) Opthalmic nerve: It is the sensory nerve.
Supply: Trigeminal ganglion.
Function: Sensation from cornea, skin of scalp, eyelids, nose and mucosa of nasal cavity.
ii) Maxillary nerve: It is also a type of sensory nerve.
Supply: Trigeminal Ganglion.
Function: Sensation from skin face of face over maxilla, upper lip, maxillary teeth, mucosa of nose, maxillary sinuses and palate.
iii) Mandibular nerve: It is a type of motor nerve.
Supply: Pons, to the muscles of mastication.
Function: Motor supply to the muscles of mastication, mylohyoid, anterior belly of digastric, tensor villi palatini and tensor tympani.
6. Abducent: It is a type of motor nerve.
Supply: Pons, to the lateral rectus
Function: To turn the eye laterally.
7. Facial: It is of a mixed type with both sensory and motor functions.

Supply:
Pons, Geniculate ganglion, Sub mandibular ganglion,
pterygopalatine ganglion, muscles of facial expression in scalp,
stapedius of middle ear, stylohyoid and posterior belly of digastric,
anterior two thirds of the tongue, to submandibular salivary glands,
lacrimal glands and glands of nose and palate.

Function:
Taste from anterior two thirds of the tongue, motor function to the muscles of facial expression and scalp.
8. Vestibulocochlear: It is a type of sensory nerve.
Supply: Vestibular ganglion and spiral ganglion.

Function:
Vestibular sensation from the semicircular ducts, utricle
and saccule related to position and movement of head, hearing from
spinal organ.
9. Glossopharyngeal: It is a mixed type with both sensory and motor functions.
Supply: Stylopharyngeus, parotid gland, acotid body, pharynx and middle ear, external ear.
Function: Assists in swallowing, taste perception from the posterior third of the tongue, cutaneous sensation from the external ear.
10. Vagus: It is also a type of mixed nerve with both motor and sensory functions.
Supply: Superior ganglion, inferior ganglion, medulla,
constrictor muscles of pharynx, intrinsic muscles of larynx, muscles of
palate, striated muscles in two thirds of esophagus, smoot muscles of
trachea, bronchi, cardiac muscles of heart, base of tongue, epiglottis,
palate.
Function: Motor function in the constrictor muscles of pharynx,
intrinsic muscles of larynx, muscles of palate, striated muscles in two
thirds of esophagus, taste perception from the epiglottis and palate,
semsation from the auricle, external acoustic meatus, dura matter of
cranial fossa.
11. Spinal accessory nerve: It is type of motor nerve.
Supply: Spinal cord, sternocleidomastoid and trapezius muscle.

Function:
Motor supply to the sternocleidomastoid and trapezius muscle.
12. Hypoglossal: It is a type of motor nerve.
Supply: Medulla, and to the intrinsic and extrinsic muscles of tongue.
Function: Motor supply to intrinsic and extrinsic muscles of the tongue