Fotografeer de beschadiging en het bestelnummer samen.

Because this is a command or instruction. In Dutch, commands normally use the imperative, and the verb comes first:

• Fotografeer ... = Photograph ...
• Kijk ... = Look ...
• Wacht ... = Wait ...

The subject is usually left out in instructions, especially in manuals, apps, and customer-service steps.

The infinitive is fotograferen. The imperative is based on the verb stem, which here is fotografeer.

This happens because Dutch keeps the long ee sound in the stem:

• infinitive: fotograferen
• stem / imperative: fotografeer

So Fotografeer de beschadiging ... is the normal command form.

Dutch nouns take either de or het as their definite article.

• beschadiging is a de-word
• bestelnummer is a het-word

Unfortunately, this usually has to be learned noun by noun. There is some help, though: bestelnummer is a compound, and the last part determines the article. Since nummer is het nummer, the full compound is also het bestelnummer.

Because both nouns are singular and each keeps its own article.

In English, you can often say the damage and the order number, and Dutch works similarly. Since one noun is a de-word and the other is a het-word, you must show both:

• de beschadiging
• het bestelnummer

So de beschadiging en het bestelnummer is the correct full phrase.

Yes. Dutch normally writes compound nouns as one word.

So:

• bestel
  • nummer → bestelnummer

This is very common in Dutch. English often uses two words where Dutch uses one:

• order number → bestelnummer
• credit card → creditcard
• city center → stadscentrum

A useful rule: in Dutch, if English has a noun + noun combination, Dutch often combines it into a single word.

Here, samen means together in the sense of include both in the same photo.

So the sentence means that the damage and the order number should be photographed together, not separately.

Its position at the end is very natural in Dutch instructions. It modifies the whole action:

• Fotografeer de beschadiging en het bestelnummer samen.

That sounds like: photograph these two things together.

In this sentence, it means the two things should be together in the photo.

Because the objects are de beschadiging en het bestelnummer, samen is understood as applying to them: put both in one picture.

If you wanted to emphasize that people are doing the action together, Dutch would usually make that clearer from context or wording.

It strongly suggests one photo that shows both items.

That is what samen is doing here. If separate photos were meant, Dutch would more likely say something like:

• Fotografeer de beschadiging en het bestelnummer apart.

So samen contrasts nicely with apart:

• samen = together / in one image
• apart = separately

Because fotograferen can take a direct object in Dutch.

So you can say:

• Fotografeer de beschadiging.
• Fotografeer het bestelnummer.

This is different from another common pattern:

• Maak een foto van de beschadiging.

Both are correct, but the grammar is different:

• fotograferen + direct object
• een foto maken van + noun

Yes. A very natural alternative is:

• Maak een foto van de beschadiging en het bestelnummer samen.

That may feel a bit closer to English Take a photo of the damage and the order number together.

Still, Fotografeer ... is perfectly correct and especially common in instructions, forms, and customer-service steps.