I often provide help desk support for congregants trying to log in to our member-responsive site, set up giving profiles, etc. In many cases it would be super helpful if I could SEE what they’re doing. But the type of people in this situation aren’t going to be comfortable doing a quick download of software so that I can remote in to them.
I agree with using Quick Assist, but that is only using Windows. With the different devices out there, it could be a nightmare to guess - better to simply ask. Alternatively, if they have a smartphone handy, you could either do a FaceTime or Google Duo session and have them point the camera at the device.
I use Team Viewer, they simply download it, run it and give me the access code they are provided in the dialog box and boom you are in. They can still control there pc but you have the ability to control it as well. Team viewer has a paid version and non paid. The non paid version is great for simple fixes and i think maxes out after half an hr of use where if you needed to get back in again, it may require a new passcode (that is provided in the TV dialog box).
Also, remote utilities could be an option as well or LogMeIn. I agree though with the comment about doing a face time or google duo/meet and just have them show you the situation.