Servisni izveštaj ima procenu troškova.

It is in the nominative singular because it is the subject of the sentence — the thing that has something.

• izveštaj = report
• servisni izveštaj = service report

So servisni izveštaj is the noun phrase doing the action of ima.

Because servisni must agree with izveštaj in gender, number, and case.

Here, izveštaj is:

• masculine
• singular
• nominative

So the adjective also takes the masculine singular nominative form:

• servisni izveštaj

This is normal adjective agreement in Serbian.

Yes. Izveštaj is a masculine noun.

A useful clue is that many masculine nouns in Serbian end in a consonant in the dictionary form:

• izveštaj
• trošak
• grad
• telefon

Because izveštaj is masculine, the adjective before it also appears in the masculine form: servisni.

Because procenu is the accusative singular form of procena.

The verb imati / ima takes a direct object, and direct objects are often in the accusative.

So:

• procena = nominative
• procenu = accusative

Since the sentence says that the report has an estimate, procena becomes procenu.

For many feminine nouns ending in -a, the accusative singular ends in -u:

• procena → procenu
• knjiga → knjigu
• firma → firmu

Because procena usually connects to what is being estimated with the genitive:

• procena troškova = estimate of costs
• literally: estimate of costs

So here:

• procenu = estimate
• troškova = of costs

This is a very common Serbian structure: a noun followed by another noun in the genitive to show a relationship like of, about, from, depending on context.

Because after procena, Serbian uses the genitive, not the accusative.

Compare:

• Vidim troškove. = I see the costs.
  Here troškove is accusative plural because it is the direct object of vidim.

But:

• procena troškova = estimate of costs
  Here troškova is genitive plural because it depends on the noun procena.

So the form changes depending on the grammar of the sentence.

It is plural because costs/expenses are usually thought of as multiple items or as a total made up of several parts.

So procena troškova is the most natural way to say cost estimate or estimate of costs.

A singular form like troška would mean of the cost, but that is less common in this kind of practical/business context unless you really mean one specific cost.

In this sentence, ima most naturally means has or contains/includes.

So Servisni izveštaj ima procenu troškova can be understood as:

• the service report has a cost estimate
• the service report includes a cost estimate

Serbian imati often works like English to have, but depending on context it can sound closer to contain, include, or feature.

Yes. Serbian word order is fairly flexible, because cases show grammatical relationships.

The neutral/default order here is:

• Servisni izveštaj ima procenu troškova.

But other orders are possible for emphasis, such as:

• Procenu troškova ima servisni izveštaj.
• Servisni izveštaj procenu troškova ima.

These are grammatically possible, but the original version sounds the most neutral and natural in ordinary usage.

Because Serbian does not have articles like English a/an/the.

So servisni izveštaj can mean:

• a service report
• the service report

And procenu troškova can mean:

• a cost estimate
• the cost estimate

The exact meaning depends on context, not on an article.

Yes. Serbian uses both Latin and Cyrillic scripts.

In Cyrillic, the sentence is:

Сервисни извештај има процену трошкова.

It means exactly the same thing. The difference is only the script.

It is a very natural noun phrase, and in many contexts it works almost like a standard technical expression.

• servisni = service / maintenance-related
• izveštaj = report

So servisni izveštaj means a report related to servicing, maintenance, or repair.

Even if it is not an idiom in the strict sense, it is a common and normal combination in technical and business language.