English is being difficult on purpose
"I have two informations for you." In most languages that sentence is perfectly normal. In English the word simply refuses to take an s, and there is no rule you can work out from meaning, because you can obviously have two pieces of information. It is just how the word behaves. The good news is that the list is short, these words repeat in almost every IELTS topic, and once you learn them the error disappears for good.
The list: these never take an s
5 fixes you will use in every essay
3 words that go the other way
Why this small thing is worth learning properly
Look at the list again and notice where those words live: education, technology, work, city life, the environment. Those are exactly the topics IELTS keeps setting. So this is not one mistake that happens once. It is one habit that repeats five or six times on a single page, and each repeat counts against your accuracy. Ten minutes on this list is one of the best trades in the whole exam.
Read next
More grammar with a real effect on your score: a, an, the: the three smallest words that cost the most marks and one comma cannot hold two sentences.
See how often you actually do it
Nobody believes they make this mistake five times in one essay, and most people do. Write your next essay in VoyaLang and look at the correction list. Every countable slip is marked in the sentence you wrote it in, so you can count them yourself and watch the number fall over the next few essays. Create a free account and check your next one in about a minute.