Forget installing apps on externals. Many reasons why we don't.
Moving on. When you install any app you have to watch for the chance to change where it installs. Windows does not do this for us and I know of no global setting to change this. Also, once you install an app, there is usually no way to move it to D: unless you uninstall and reinstall.
I have an Inspiron 15 7000 computer and am running out of storage. When I go to manage storage This PC C: is nearly full but Data D: has plenty of room. What is Data D: and can I use it for further storage? I have tried to manage storage spaces and change where things are now downloaded to so they are now saved to Data D: but it doesn't always work. For example when I updated photoshop it was able to use space in Data D: but when I tried to download the program Revit only part of it was able to save to Data D:. I was thinking that I might need to get an external hard drive but was reading about how that is used more for backing up files. My issue is that I have a lot of programs that I need to use and it sounds like you are not suppose to save programs to external hard drives. Any suggestions at all would be great. Thanks