As of know, upon installing Trados Studio, a subfolder called Studio 2019 will be created in your personal Documents folder. When you install MultiTerm, a subfolder called SDL will be created in your personal Documents folder. I have found no way to change these default locations to somewhere else. I certainly do no want these files in my Documents folder, without even a chance of renaming them to something more meaningful for me.
Creating arbitrary working folders in personal user folders is a typical habit of adware and bloatware, and I'm sure SDL software can do better than this.