If you already have a account:
Minecraft Java Edition is premium software. It costs money (usually around $29.95 USD). It is not free-to-play like the mobile or console versions (Bedrock). minecraft 1.12 2 download free java edition
Unfortunately, Minecraft is a copyrighted game, and downloading it for free without purchasing it may be against the terms of service. However, here are some legitimate ways to obtain Minecraft 1.12.2 Java Edition: If you already have a account: Minecraft Java