Qlik Sense does not require a client. Using Qlik Cloud, you can use Qlik Sense on any of its supported browsers. See System requirements and supported browsers for details.
If you are using Qlik Sense Enterprise on Windows (on-premise), then the Qlik Sense Desktop client can only be installed on Windows and on a 64-bit environment. You can, however, connect to the Qlik Sense server from any supported browser. See Supported Browsers | Qlik Sense Enterprise on Windows for details.