How to setup remote access on a Mac
Who is supporting your network at your company? An "IT" department? You? An outside company/managed service provider (MSP)?

IT Dept - ask them if they can offer a VPN connection for remote access.

MSP - ask them if your firewall supports a VPN connection for remote access. If it does, ask them what is required to set it up (this may be billable).

You - you're probably in over your head. To start with, you need to know what kind of firewall you have.