More information about internships abroad in the International Relations Bureau of the UPC's website.
You will have to fill in the Traineeship Agreement thrice (once for you, once for the company and once for the FIB).
If the company is in one of the lands in the Erasmus+ programme (KA103 or KA107) you can, also, request the Erasmus+ Traineeship grant.
The interships may last from 2 to 12 months per study cycle, leaving out the months already taken from previous Erasmus+ calls. For any duration, at most 3 months of stay will be financed per academic year.