Payments company Square said Wednesday it will buy Credit Karma's tax business for $50 million and integrate it into its Cash App, a major hub for bitcoin sales.

Cash App will make Credit Karma's do-it-yourself tax-preparation software available to its 30 million monthly users for free, Square said. Those users already send payments, manage credit cards, invest in stocks and increasingly purchase bitcoin from the popular app.

Credit Karma is selling the operations as a condition to gain U.S. Department of Justice approval for its $7.1 billion acquisition by Intuit.