What is software that is completely free?

Software that is completely free comes in three genuinely different kinds. They are worth telling apart because 'free' hides different deals: open-source software (free forever, source code public, run by communities or companies: LibreOffice, GIMP, VLC, Blender, Linux; the license guarantees it stays free), freeware (free to use but closed: the vendor can change terms, add ads or discontinue it anytime), and free tiers of commercial products (free until you hit limits designed to convert you; generous ones are honest value, stingy ones are extended trials).

The classic warning applies mainly to the middle category: if a closed product is free and you can't see the business model, you might be the product (data, ads, upsell).

Open source is the safest 'completely free' bet. The incentive structure can't quietly flip on you.