Questions & Answers about Izvadak mora biti čitljiv.
Izvadak is the nominative singular form, because it is the subject of the sentence.
In Izvadak mora biti čitljiv, the thing that must be legible is izvadak, so Croatian uses the basic dictionary form here.
A native English speaker may notice there is no article. Croatian normally does not use words like the or a/an, so izvadak can mean the extract/document/excerpt depending on context.
Mora is the 3rd person singular present tense of the verb morati, which means to have to / must.
So:
- ja moram = I must
- ti moraš = you must
- on/ona/ono mora = he/she/it must
Since izvadak is grammatically singular, the verb is also singular: mora.