I am trying to create a boot usb to repair my Windows 10 computer using EasyBCD Support. When I get to the Add New Entry, the options at the bottom are not available. Do I need to use a Windows 10 computer to create this bootable USB or can I use a Windows 11 computer?
You can use a Windows 10 or a Windows 11 PC, but I'm guessing you are booting in EFI mode which disables a number of features due to restrictions and limitations imposed by Microsoft.
Amended post: no, not using EasyRE, but you can use a Windows 11 machine to create a bootable Windows 10 USB Drive using the Full Windows 10 ISO from the download page at Microsoft.com.
EasyRE is not a full system ISO for copyright reasons.