TAMUS UIN vs. TAMU NetID
Note that your UIN is issued by the TAMU System and not the local campus.
Other than yearly applications (perhaps?), we will never ask for your UIN.
99.9% of the time we will want your NetID (see below) in order to help you.
Although this may be on your student/employee ID, this number is rarely needed for accessing systems on the TAMU campus. Exceptions might be the office of the register, the office of identity or https://sso.tamu.edu/.
As mentioned above, this is a pseudo-SSN. As such, you should treat it with some care. You don't need to make it as private as your social security number (which you should always keep secure) but you don't need to make it as public as your phone number. Please don't include it in any emails to HPRC unless specifically requested to.
95% (a guess) of logins on the TAMU campus will want your NetID. This was issued by the local campus Division of Information Technology. In most cases, it will be the part that comes before @tamu.edu in your email address.
Your NetID will be what you will use to access HPRC systems.
If you have more questions about UINs and NetIDs, please see TAMU IT's Accounts and ID Management page