Scrivener on my new Mac

I have installed Scrivener program a year ago on my previous Mac in the office.
Now, my manager ordered a new Mac for me and try to wipe out all the program on my old mac.
Under this circumstance, Is there a way I keep my installation file from my old computer
and reinstall it on my new Mac? or I have to purchase a new one again.
What is the best way to use the application on my new Mac?
Thank you for your advice in advance.

From Houston

Just download the same version you had on the old mac, locate the license key in your email, and input that when prompted to.

What version are you running on the old Mac?