If you are computer-literate, you can use a computer for ordinary work: open it, write something, send a message, find things on the internet. It does not mean you can write programs or mend a broken machine. It only means you are not lost in front of a screen. The word copies literate, which first meant “able to read and write,” and then people stretched it to “able to use this tool.” You see it on job ads and in school reports more than you hear it among friends. Though actually, the bar keeps moving. What counted as computer-literate twenty years ago is basic now, and many young people barely use the word, because they assume everyone can already do this. Older speakers still use it for quite simple skills. It is a calm, slightly formal workplace word, not a claim that you are an expert.