You need an active internet connection during activation, even though Ufile works offline afterward.
Your key location depends on how you bought UFile: Ufile Activation Key
A single activation key allows you to install UFile on up to two (2) computers owned by you. Return Limit: You need an active internet connection during activation,
Activation is a secure process designed to prevent unlicensed use while remaining anonymous. Ufile Activation Key
As long as you have not exceeded your return count, you can install Ufile on a new computer and re-enter the same key. The server tracks usage. If you get an error, use the "Deactivate" option in the old software before crashing, or contact support to release the license.