The following is provided for your convenience. For the exact terms of the computer version license, please read the LICENSE file distributed in the Anki source package.
You are free to use the computer version of Anki in a school or company. As per the terms of the license, if you modify Anki, you must make your modifications publicly available.
A copy of AnkiMobile must be purchased for each user who wants to use it. Volume licensing is available for academic institutions.
The cards you create with Anki are your own, so you are free to license them as you please, and sell them if you wish. Anki does not include any DRM features to prevent users from sharing decks, as its open-source nature means any such protections could be bypassed easily. If your decks turn up on the Internet in violation of your copyright, you are of course free to send takedown notices. If you find your copyrighted content has been uploaded on AnkiWeb's list of shared decks, please let us know and we will remove it as soon as possible.
We do not have the resources to create custom versions of Anki, AnkiMobile, or AnkiWeb at this time, whether to add DRM or other features. You are free to modify the desktop version of Anki yourself in accordance with the license.
AnkiWeb is intended for individual users. People in a school or company are welcome to sign up for their own accounts, but teachers or company staff should not create accounts in bulk for people. AnkiWeb does not currently provide any means of monitoring activity on students' accounts.
Because AnkiWeb is a free service targeted at end users, we do not have the resources to sign data processing agreements and similar documents with schools or companies. If you require such documents, alternative products like Quizlet may be better able to accomodate you.