Wir reichen die Taxiquittung später nach.

Because the verb here is nachreichen, which is a separable verb.

• The full infinitive is nachreichen = to submit later / to hand in afterward / to provide afterward
• In a normal main clause, the verb splits:
  • reichen goes to the usual verb position
  • nach moves to the end

So:

• Wir reichen die Taxiquittung später nach.

Compare with the infinitive:

• Wir müssen die Taxiquittung später nachreichen.

In that sentence, the verb does not split because it stays in the infinitive.

In this context, nachreichen means something like:

• to submit later
• to provide afterward
• to send in afterward

It is often used when a document, piece of information, or item is missing now but will be provided later.

So this sentence suggests that the taxi receipt is not being handed in right now, but it will be added later.

Taxiquittung is a feminine noun, so its basic article is die.

Here it is also the direct object of the verb, and in the accusative feminine, the article is still die.

So:

• nominative: die Taxiquittung
• accusative: die Taxiquittung

That is why you do not see a visible article change here.

It is in the accusative case because it is the thing being submitted.

In the sentence:

• Wir = subject, nominative
• reichen ... nach = verb
• die Taxiquittung = direct object, accusative
• später = adverb

A useful question to ask is: What are we submitting later?
Answer: die Taxiquittung.

That makes it the direct object.

German main clauses usually follow the V2 rule: the finite verb goes in the second position.

Here the sentence begins with Wir, so the finite verb comes next:

• Wir | reichen | die Taxiquittung später nach.

This is standard German word order for a main clause.

If you move another element to the front, the verb still stays second:

• Später reichen wir die Taxiquittung nach.

Notice that reichen is still the second element.

Because nach is not acting as a normal adverb here. It is the separable prefix of nachreichen, and separable prefixes go to the very end of the clause.

So später comes before that final prefix:

• Wir reichen die Taxiquittung später nach.

You can think of nach as belonging to the verb, not as an independent word like later in English.

Grammatically, it is present tense:

• Wir reichen ... nach.

But in German, the present tense is very often used to talk about the future when the time is clear from context.

Here später makes the future meaning obvious, so German does not need a special future form.

English does something similar:

• We’ll submit it later
• We submit it later would sound less natural in English, but German uses the present tense very naturally here.

A more explicitly future version in German would be:

• Wir werden die Taxiquittung später nachreichen.

But that is not necessary in most everyday situations.

Yes. German often forms compound nouns, and they are written as one word.

Here:

• Taxi = taxi
• Quittung = receipt

Together:

• Taxiquittung = taxi receipt

This is completely normal in German. Also, all nouns are capitalized, so Taxiquittung must begin with a capital letter.

This is a very common question.

• Quittung = receipt, proof that something was paid
• Rechnung = bill or invoice, a request for payment

In this sentence, Taxiquittung is the correct word because it refers to the receipt you get after paying for the taxi.

So if you are claiming expenses, for example, you would usually need the Quittung, not the Rechnung.

Yes, that is also possible.

German word order is somewhat flexible, especially with adverbs and objects, as long as the main structure stays correct.

Both of these are natural:

• Wir reichen die Taxiquittung später nach.
• Wir reichen später die Taxiquittung nach.

The difference is mainly one of emphasis or rhythm.

• die Taxiquittung earlier: slightly more focus on the document
• später earlier: slightly more focus on the timing

Both are grammatically fine.

It is fairly neutral and very common in formal or semi-formal contexts, especially for documents, receipts, forms, or information.

You might see it in:

• office communication
• expense claims
• applications
• customer service
• emails

It sounds natural in practical situations where something is being provided after the original moment.

So yes, it fits well in administrative or business contexts, but it is not so formal that it sounds unnatural.