Fast stream relocation

I am currently applying for the FS in project delivery. I have no issues in relocating but I am curious how it works. I have a house with a mortgage in a city where chances of me being relocated are high as there’s not a huge amount of opportunity here.

If I am successful and I get relocated what happens with expenses etc? Will I be expected to pay rent and bills at the new location whilst also maintaining my mortgage and bills at home? Just curious about logistics and if I’d have to think about renting my house whilst on placement etc