To move it to an external drive for use on the same machine, just move the folder holding the application (e.g. the Studio folder in C:Program FilesDAZ) and in Edit>preferences>Directories change the paths for the DAZ Studio and Poser content directories that have moved.

If you want to make a stand-alone (except for content directory listing and serial number) version, you need to add the daz*.dll and dz*..dll files from WindowsSystem32 (or the matching .dylib files n the Mac, I never can remember where they live) to the folder on the external drive.