"She did not know it."
Translation:Hun vidste det ikke.
Usually, in a simple sentence like this, "ikke" comes at the end of the sentence. Even if you flipped it around (which you can in Danish), and said "Det vidste hun ikke", ikke still comes on at the end, unless you want to put a strong emphasis on "det" (I.e. She didn't know THAT), then you can actually put it right behind the verb.
If a sentence has an indirect object, the "ikke" is sometimes placed somewhere else. For example: She didn't give the present to him/She didn't give him the present.
"hun gav ikke gaven til ham"/"hun gav ham ikke gaven"
This is because there is motion in the sentence. If something is going somewhere (the present going to him), then it is placed directly after the verb. For example: We didn't go over there / We didn't run home
"Vi gik ikke derhen"/" Vi løbte ikke hjem"
(I'm really sorry) but, "ikke" can also come directly after the subject of a sentence. This is only done in two situations:
Situation 1. If the sentence is a subclause (usually right after the word "that") For example: We didn't know that she didn't know it
"Vi vidste ikke, at hun ikke vidste det"
Situation 2. If a time or place is mentioned in the beginning of a sentence, and if there is no object. (note that this type of sentence also changes the position of the verb) For example: Yesterday, she didn't know
"i går vidste hun ikke"
Situation 2.5. If there is an object in situation 2, then i comes after the object.
I'm sorry if this is a bit complicated, I'm not that good at explaining things.