Acctivate is a Windows application, but can be accessed from a variety of devices using a Remote Desktop connection.
There is not a native iOS or Android app for Acctivate. However, both the iTunes App Store and Google Play Store offer Remote Desktop apps. You can install a Remote Desktop app on your device, then configure a connection to either your Desktop PC or a Terminal Server on your work network. The windows in Acctivate work well on all tablets with a screen of 7″ or larger.
Microsoft Remote Desktop
Microsoft has published their Remote Desktop app for all platforms. This is the official Remote Desktop app from Microsoft. It should be the most stable for accessing your Windows desktop or server computer. The Microsoft app offers a simple mechanism for pan/zoom and a button to toggle the keyboard. However, this app will require your IT/network support to set up a secure Remote Desktop gateway or port forwarding to access your work computer outside of your firewall.
WYSE Pocket Cloud
WYSE PocketCloud is an excellent choice for both iOS and Android devices. PocketCloud can remotely connect to either your desktop computer at the office or a Terminal Server, just like the Microsoft Remote Desktop app. The main difference is that Pocket Cloud offers a unique mouse pointer with quick access to the keyboard, shortcuts such as copy/paste and other tools. The free version allows connection to a single computer, the Pro edition is recommended to connect to multiple computers, including your server.
Jump Remote Desktop
Jump Desktop is another excellent choice for the Mac OS X, iOS and Android platforms. This is a great app if you needing to access your work PC from your home computer running Mac OS X an iPad and maybe your Android phone. Jump uses your Google (Gmail) account to securely manage your list of computers for remote access. You should be able to set up your remote connection without any changes to your network.