There is no native Mac version of Mathcad.
If your license allows you to install Mathcad on more than one machine, you may run it on a Mac basically in three different ways (like any Windows software):
1) Dual Boot Configuation: Use Boot Camp to install Windows alongside macOS (you'll need a Windows license to do so)
2) Virtual Machine (Parallels desktop, VMWare, Virtual Box, Citrix,...): Run Windows and Mathcad in a virtual machine (again you'll need a Win license). If your Windows machine still is alive you may even turn it into a VM and run that on the Mac (this will not work with parallels desktop AFAIK).
3) Use a Windows emulator like WINE or CrossOver Mac. You don't need a windows license but the emulators are far away from being perfect. No guarantee that a specific Win software will run flawless in the emulator. Furthermore PTC will not provide any support for running their software in an emulator (but losing PTC's support is not a big loss anyway).
If possible I would go for a virtual machine. IMHO It provides a good balance between reliability and comfort.
Having to reboot just to be able to use a specific software as in a dual boot config can be annoying and using an emulator is not that reliable as I would wish it to be (though I have no personal experience in using Mathcad with a windows emulator).
Maybe we have some Mac users here in the forum who have personal experience and give some further advice.