Type the amount, get the exact wording your bank expects — with the standard fraction and 'Only' that prevents alteration.
Banks require the amount written in words as a fraud-prevention check against the numeric amount box. The standard format spells out the whole-unit amount, then shows cents (or the relevant subunit) as a fraction — "One Thousand Two Hundred Thirty-Four and 50/100 Dollars Only" — with "Only" at the end so nothing can be added after your writing.
That's the actual banking convention — cents appear as a fraction of the currency's smallest unit, not spelled out in words, unlike a legal contract amount.
This is a real anti-fraud standard, not a formatting quirk — leaving it blank would make the cheque easier to alter.
Yes, all 65+ supported currencies work, including ones with 3 decimal places like the Kuwaiti Dinar, which correctly shows a fraction out of 1000.