Krita is licensed under the GNU General Public License (GPL), version 3. This license gives you the following rights:
Krita as a whole is licensed under GPL v3. Parts have more permissive licenses, this is indicated in each source file. Our builds of Krita also include third party libraries licensed under the GPL or a more permissive license. Our source code shows exactly where you can get the source for those libraries and includes our changes to those libraries.
Krita can be extended with plugins written in C++ or Python. The extension API is an integral part of Krita and is licensed under the GNU General Public License. This means that if you distribute a Krita plugin it also has to be shared under the GNU GPL. You can charge for the download, but you cannot prevent others from distributing your plugin: your customers will have all the rights guaranteed by the GNU GPL.
What you create with Krita is your sole property. All your artwork is free for you to use as you like. There are no restrictions whatsoever when it comes to what you use Krita for.
That means that Krita can be used commercially by artists, by scientists for research, and by students in educational institutions.
Kritas GNU GPL license guarantees you this freedom. Nobody is ever permitted to take it away, in contrast to trial or “educational” versions of commercial software that will forbid your work in commercial situations.
Krita respects your privacy, no registration is needed, no connection to the internet is made if you decide to install and use Krita.
Krita does not need internet to function properly. Only if you enable the Recent New feature in the startup screen will Krita use the internet to download the news. Downloading the recent news will not lead to any tracking.
If Krita is installed using Steam or the Windows Store, those stores will use the internet to check for updates.
Your Operating System might track your usage of Krita: Windows registers every executable you run with Microsoft. We do have access to the statistics, but there is nothing that can be tracked down to any individual user.