The HUB designation is a custom registration field that organizations in Texas often ask for. It refers to a designation under the State of Texas' Historically Underutilized Business Program: http://uthscsa.edu/business/hub/
If you do not qualify for this designation, most Vendor Registration forms have N/A as an option. Select that option to proceed.
Note
If you have any further questions about this certification, reach out to the organization that you are registering your Vendor account with, as they are more qualified to answer. Euna Procurement is not officially associated with the HUB program in any way.