Costume is not required for Planetfall at all, but in envisaging your character or choosing to costume them we present suggestions for style.
In particular it's worth noting that Species does not determine culture and thus does not determine clothing or style. Sure, individual species will have preferences and practical modifications to make (e.g. room for tails for Vyixians, lighter weight fabric for the cold-blooded Ziline, adaptations for the armour plates of Chirrids), but the appearance and choice of clothing is not restricted by that.
This list is by no means exhaustive - worlds are far more than a simple charicature and should not be considered as such! - this simply serves to provide an idea.
Styles are a lot more varied in the far more populated worlds of the Galaxy, but some elements can make an individual stand out as calling a world home:
The following elements should not make their way into costuming for Planetfall: