In basics for devops course > services section, the instructor says the default location for a systemd unit file can/may be at /etc/systemd/system. This can be further deduced to understand that there are alternative locations for the unit files. But there is no further clarification in the video lecture or the lab to know of the other possible locations for unit files to exist.
The labs section creates and uses files from /usr/lib/systemd/system location. There is even a multiple-choice question designed around this. But this path is never discussed in the video lecture. This mismatch causes a novice like me to choose wrong answers until I find the right one. Furthermore, once the actual hands-on lab sections start requiring checking on the pre/post startup instructions, although the unit files are used from /usr/lib/systemd/system path which I learned from the earlier multiple-choice question, it leaves me wondering what (if any) other locations are allowed and if I can create my own unit file at a random location. If this is allowed, how would I configure my new random location in the system settings so that daemon-reload command picks up my new unit file.