"anrufen" is a separable verb. in affirmative sentences in the present tense, the verb separates to form the so-called "Verbklammer": the first part is the conjugated bit (your left bracket), then you have all of the objects in between (adverbs of time, cause, modus and place) and then the preposition "an" goes straight at the end of the sentence (the right bracket). Note that when you form the past participle of separable verbs, the "ge-" goes in mid position: Anrufen -> to call / anGErufen -> called
Lowercase is also they.
You can generally tell her from they or formal you by the conjugation of the verb.
Sie isst. She eats. Sie/sie essen You eat/they eat.
They vs formal you can be identified by the case of the first letter unless it is at the beginning of the sentence. Then your only clue will be context which is often not present in the short sentences we do here.
When it's she eats - sie(lower case) isst is correct..? And they eat - sie(lower case) essen.. Correct..?
Both correct -- with the caveat that the first letter of a sentence is always capitalised.
So "I eat and she eats." is Ich esse und sie isst. but "She eats." on its own is *Sie isst."
Similarly, "We eat and they eat." is Wir essen und sie essen. but "They eat." on its own is Sie essen.
No, those are all wrong. Ihnen is dative, not accusative.
Ich helfe Ihnen, ich folge Ihnen, ich danke Ihnen are fine because those verbs take an object in the dative case, but your examples would have to be Ich sehe Sie, ich habe Sie, ich mag Sie -- and also ich rufe Sie morgen an.
Wrong from which point of view?
As far as I can tell, this sentence discussion is for something where Duo provided something in German. (If this had been a "translate English to German" exercise you were asking about, I would have expected your question in https://www.duolingo.com/comment/9919851 .)
Since you are asking about a German sentence that was presumably rejected, I'm guessing it was a "type what you hear" exercise.
That is, you heard a German sentence and had to type what you heard. You typed "Ich rufe Sie morgen" and that was rejected, and you would like to know why.
In that case, the answer is: you're supposed to type what you hear. The voice says "Ich rufe Sie morgen an", so if you type "Ich rufe Sie morgen", the thing that's wrong is that you left off a word.
If you are instead asking: "I see that Duo uses the sentence Ich rufe Sie morgen an. Would the sentence Ich rufe Sie morgen. also be possible? If not, why not?", then I'm not sure why you would use the word "what's wrong" in this respect.
Or if you are asking: "I see that Duo uses the sentence Ich rufe Sie morgen an. but I believe this sentence is wrong. I think that Duo should have used the sentence Ich rufe Sie morgen. instead. Why did it not use that sentence? Am I wrong and there is something wrong with Ich rufe SIe morgen.?" then that question has another answer.
If, for some reason, you had an English to German translation exercise where you were asked to translate "I will call you tomorrow." and you answered Ich rufe Sie morgen. and wonder why that was not accepted, yet the discussion somehow brought you here, I don't know why that would be. I suggest you have a look at the sentence discussion for the opposite direction that I linked to above.
If your question had some other reason, please provide a bit more context as I'm not sure what you are trying to ask.
Thanks for clarifying.
It would be grammatically correct but a bit unlikely in real life.
anrufen is to call someone on the phone, rufen is to call someone with your voice.
If they're still going to be in earshot tomorrow, waiting for you to call them over with your voice to where you are, they're going to be pretty patient.
"call" + "tomorrow" makes it most likely to be a telephone call, so ich rufe Sie morgen is an unlikely translation. (And is not accepted by Duolingo at the moment, as it happens.)
(Things are different with die Polizei rufen, einen Arzt rufen.)
I believe that "I call you tomorrow" should be accepted too. Even in English a sentence in present tense can refer to the future (https://en.wikipedia.org/wiki/Future_tense#English)
Not only "morning" and "tomorrow" are related but also "evening" and "yesterday" in some languages -- for example, večer "evening" and včera "yesterday" in Slovak.
Perhaps it's because if you go to sleep, then when you wake up it is "tomorrow morning", while the last thing you remember before you went to bed was "yesterday evening".