Hello,
It depends, whether you have a DVR, which can be connected to the internet.
Does it have ethernet ports? Wireless capabilities?
If it does, depending on whether you have a public IP or not, at the basic level port forwarding, VPN or Teltonika's Remote Management System could be used as a solution to access the DVR.
Also, does the DVR itself have an app/platform/software for it's management and remote access?
Best regards,