Find ice blocks in snowy biomes, frozen oceans, frozen rivers, and ice spikes biomes
Use a tool enchanted with Silk Touch to mine the ice block
Break ice with any other tool or by hand to get water instead of the block
Trade with a wandering trader for packed ice in some versions
Find ice in generated structures such as igloos or certain snowy village areas
Use commands in Creative mode to obtain ice directly
Craft blue ice from packed ice if needed for faster travel
Place water in a cold biome and let it freeze into ice