Freeview is a UK TV service. It is transmitted from land based masts, and received by TV aerials. Due to this Freeview UK is NOT availabel in Spain, as those "terrestrial" mast signals simply do not reach Spain, heck they dont even cover the whokle of the UK!
So, you cannot receive Freeview UK in Spain.
You can receive Freesat, the satellite ewquivilent, using a large enough satellite dish, and a satellite receiver. Chanenls like BBC ITV C4 and Fives are all available subscription free. But note that some chanensl that are available for free on Freeview, are pay (Sky) on satellite.
Although, as pointed out Spain has its own version of Freeview, television digital terrestrial (TDT), which like Freeview, provides digital tv channels via a tv aerial. There areno "UK" chanenls on TDT (although one of my local chanenls does broadcsat BBC WOrld NEws for a few hours each day), but if the programmes looks like it is importred from the UK or USA, then most of the time you can change the audio from the dubbed Spanish into English.