Find clay blocks underwater in rivers, lakes, swamps, beaches, and oceans
Break clay blocks with any tool or by hand to get clay balls
Use a shovel to collect clay blocks faster
Smelt clay balls into bricks if needed
Trade with a mason villager for clay
Loot clay from some chests in generated structures
Use a Silk Touch tool to pick up clay blocks directly
Dig underwater riverbeds and shorelines where clay is common