Feature Name corresponds to the name of what a PTC product is called in the PTC Startup File (PSF) file, see more information here. These can be looked up in three places:

1. License File

When you receive the Electronic Software Delivery (ESD) from PTC and have floating licenses for PTC products managed via FlexNet, you will be prompted to receive a license file that you then enter into FlexNet. In the license file will be a list of the products you are receiving along with their feature names (shown below). 

2. PTC Portal - License Management 

If you login to your account on support.ptc.com. Select the "PTC Licensing Tools" option under the "Tools" tab at the top right. 

Then choose "Advanced Search" option under the "License Actions" tab and select the "Search" button.

From there, a list of the products you own will appear under the "Available License" tab or if they are already installed to a Host, in the "Installed License" tab.

3. FlexNet Server

If you have a FlexNet Server set up, you can navigate to it, login, and find the PTC Feature Name you need (shown below).