Mallampati score is for:
Ref. Oxford textbook of anesthesia. Page. 397
 
Modified Mallampati classification 

Class 0: Ability to see any part of the epiglottis upon mouth opening and tongue protrusion
Class I: Soft palate, fauces, uvula, pillars visible
Class II:Soft palate, fauces, uvula visible
Class III: Soft palate, base of uvula visible
Class IV: Soft palate not visible at all

Test: The assessment is performed with the patient sitting up straight, mouth open and tongue maximally protruded, without speaking or saying “ahh.
Inspection of oral cavity
Tracheostomy
Intubation
Assessing airway