Questions & Answers about Die Katze ist auch hier.
How would I say 'A cat is also here' instead of 'The cat'?
You would change the definite article Die (the) to the indefinite article Eine (a). Because Katze is a feminine noun, you must use the feminine form eine instead of ein.
Why is the word ist in the second position?
In regular German statements, the main verb must always be in the second 'slot' of the sentence. Here, the entire subject Die Katze takes up the first slot, so the verb ist (is) naturally comes right after it.
Why does the word auch come right before hier?
In German, auch (also/too) usually sits right in front of the specific idea it emphasizes. By putting it right before hier (here), the sentence highlights that the cat is in this specific location along with whoever else is already here.
Does die Katze change to a masculine word if the cat is a boy?
No, the grammatical gender of the word Katze is always feminine, so it always uses feminine articles like die (the) or eine (a), no matter the animal's actual sex! If you specifically need to point out a male tomcat, Germans use a completely different word: der Kater.