To undo changes in Git, you can use the following commands, depending on what you want to undo:

Method 1: Undo uncommitted changes in the working directory:

git checkout -- <file>

Method 2: Unstage a staged file:

git reset <file>

Method 3: Undo the last commit but keep changes:

git reset --soft HEAD~1

Method 4: Undo the last commit and discard changes:

git reset --hard HEAD~1

Choose the command based on your requirement. Always be cautious with --hard as it irreversibly deletes changes.