There are many ways one can remote into another computer, and various reasons to do so. By far the combination that happens most of the time in my daily life is remoting into another computer in order to help someone. I use an older version of TeamViewer, because it is the one our institution licensed at the time. We have recently moved to using Zoom instead, which has some significant drawbacks when used this way.
TeamViewer
Zoom
Remote Desktop Connection (built into Windows)
LogMeIn
RAdmin
VNC
Synergy