Usually, you will build a file server by repurposing an older computer or server using free NAS software, such as TrueNAS, or purchase a dedicated NAS, such as those available through Synology.
Or, you could go a little bit more complicated and create a VPN on the NAS so that you can access everything, which is the ...
TeamViewer is one of the go-to remote desktop applications that people know of, but it's nowhere near the best. While it was one of the first to make unattended access easy and made it possible to do ...