As i understand, you asked how to get the trial license of Mathcad.
For Mathcad Prime
Option 1: Retrieve a trial license via internet
Install and launch Mathcad Prime
Click top left Mathcad Prime icon(M') > select Options from the drop down menu
Select License tab> Get trial License
Option 2: Manual license file via e-mail
Log a support case using Mathcad Case Loggerwith the Host-ID(MAC address) of the machine ( Start> execute>cmd> OK> ipconfig/all (enter)> Connexion Ethernet locale Network card OR WiFi> Physical adress.