Go to the official Minecraft website: https://www.minecraft.net/
Click Buy Minecraft
Choose Minecraft: Java & Bedrock Edition for PC
Sign in with a Microsoft account
Complete the purchase
Download the Minecraft Launcher
Install the launcher on your PC
Open the launcher and sign in
Select Java Edition or Bedrock Edition
Click Play to download and start the game
If you already own Minecraft, download the launcher and sign in with the same account