Learn Croatian: Moraš odmah platiti račun. - You must pay the bill immediately.

In Croatian, when you use a modal verb like morati (must), the main verb that follows it stays in its base dictionary form, called the infinitive. Since moraš already shows who is doing the action (you), platiti (to pay) doesn't need to change endings.

Where is the word for 'you' in this sentence?

Croatian often drops subject pronouns like ti (you) because the verb ending already tells us who is doing the action. The -š ending on moraš makes it perfectly clear that 'you' must do it. You could say Ti moraš, but the pronoun is usually left out unless you want to add special emphasis.

Is račun in the accusative case here? It looks exactly like the dictionary form.

Yes, it is in the accusative case because it is the direct object (the thing being paid). However, račun is a masculine inanimate noun (a non-living thing). For non-living masculine nouns in Croatian, the accusative form is exactly the same as the nominative (dictionary) form.

Can I change the word order and put odmah at the end of the sentence?

Yes! Croatian word order is quite flexible. You could say Moraš platiti račun odmah if you really want to emphasize the word 'immediately', but keeping it as Moraš odmah platiti račun sounds very natural and is a standard way to phrase it.