Armor

Armor (p.36) md

The PHB armor rules apply in Oath-Bound as written. Armor class, the armor table, and the relationship between armor type and protection are unchanged.

Not all armor types listed in the PHB are necessarily available in every campaign setting or region. The GM establishes which armor types exist, can be sourced, and are culturally appropriate to the specific campaign at Session Zero or as the fiction warrants. A character whose background places them in a society that does not produce or trade in plate armor cannot simply purchase it at the equipment table.