Ini is this, itu is that. The split is by distance from you, exactly as in English.
Sentences with no verb
Indonesian has no equivalent of “is” or “are” in this kind of sentence. You put the two things next
to each other and you are done.
Ini kopi. ‘This is coffee.’
Itu rumah saya. ‘That is my house.’
Learners often reach for a missing verb and try to insert adalah. Leave it out. Adalah exists but belongs to definitions and formal writing, and in a spoken sentence like these it sounds wrong.
Asking
Apa ini? ‘What is this?’
Ini apa? ‘What is this?’
Both orders work. The second is more common in speech.
Itu doing the work of “the”
Indonesian has no articles, but itu placed after a noun points at a specific one, which is close to what English “the” does.
Buku ‘a book, books’
Buku itu ‘that book, the book’
This is one of the small compensations for having no articles to learn: when you need to be specific, you add a word, and the rest of the time you say nothing.
Attached to adjectives
Ini and itu also stand in for a whole situation, the way English uses “that” alone.
Itu mahal. ‘That’s expensive.’
Itu enak! ‘That’s tasty!’