Placement year while studying planning

Hi, I understand this is a bit of a niche question but thought id try anyway. Going to study planning and considering cardiff, and have been leaning towards doing a placement year as-well as a part of the degree. However thought it was abit too early to be 100% sure at this point, so wondering if it’s possible to decide later at university wether to take the placement year or not? If it is possible, does it work both ways? (As in can you apply for the course without a placement year and then decide to take it/or the opposite) Thanks!