A file with the ICA file extension is most likely an Independent Computing Architecture settings file used by Citrix programs. The ICA file launches a remote application using the either Citrix XenClient or the Citrix XenApp program. Though you can open an ICA file with a text editor to view the contents, you can only launch an ICA file with one of the compatible Citrix applications.
Right-click on the ICA file to open the File context menu.
Click the "Open With" option. A list of programs opens.
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Scroll to and click on the "Citrix XenApp" or "Citrix XenClient" program. The Citrix program opens and launches the remote application defined in the ICA file.