Is Kopie der, die or das?

The correct German article for Kopie is die. The noun Kopie is Feminine. So you always say: die Kopie. Learn the article together with the noun — German nouns don't follow predictable gender rules most of the time.

The plural of Kopie is: die Kopien. In the plural, every German noun takes the article "die". So: die Kopien. Example: ein Kopie → zwei Kopien.

Correct: die Kopien. The form "die Kopies" is wrong. The plural of die Kopie is die Kopien. In the nominative plural, you always use the article "die".

die Kopie follows the four German cases. Nominative: die Kopie, Accusative: die Kopie, Dative: der Kopie, Genitive: der Kopie. In plural: die Kopien / den Kopien. Learn these forms together with the noun.

The genitive singular of die Kopie is: der Kopie. The genitive plural is der Kopien. German uses the genitive to express possession or belonging. Example: die Farbe der Kopie.

The dative plural of Kopie is: den Kopien. In German, dative plural nouns usually end in "-n". So you say: "mit den Kopien". Use this case after prepositions like mit, von, bei, zu.

Kopie ends in -e. German nouns with this ending are almost always feminine. Nouns ending in -e are often feminine (die), especially two-syllable words. That's why the article for Kopie is die.

Kopie is a noun and must be capitalized in German. You'll find example sentences above for each case. The article die stays the same in nominative singular but changes in other cases. Practice declension in your own sentences.

Yes, Kopie is a noun (also called a substantive). German nouns are always capitalized. The article for Kopie is die. Every German noun has a fixed article you must memorize.