you should start reading existing comments.
Kawa - is nominative singular form - one that is shown in dictionaries, written on labels, receipts and menu, it is a form that is used when the word is used as subject of the sentence.
Kawę - (with "tail", there is no such word as "KAWE") is accusative singular form. It is used as direct object of most verbs in positive sentence.
For example "Piję kawę"= I am drinking coffee, Poproszę kawę- Coffee, please (literally "I will ask for coffee")