To identify your host, you will need to download the license management utility (lmutil) and run it on the computer where you are going to install the product (for standalone license) or on the license server (for server licenses).
For Windows hosts:
> cd /d "C:\Users\User Name\Downloads\"
> lmutil.exe lmhostid -ether
For Linux hosts:
$ cd ~/Downloads/
$ chmod +x lmutil*
$ lmutil* lmhostid -ether
When you run lmutil, it reports the host ID, for example:
lmutil - Copyright (c) 1989-2013 Flexera Software LLC. All Rights Reserved.
The FlexNet host ID of this machine is "e05806420eb4"
Copy the quoted string of characters ("e05806420eb4") to the Host ID field in the request form. Sometimes the host ID contains two or more strings, for example "e05806420eb4 38d547e18e73". In this case, copy the entire quoted string with spaces to the Host ID field.