Add a file to the staging area
git add <file>
To add all files in the current directory, use . in place of <file>.
git add .
Commit Changes
Commit changes that are already tracked and staged
git commit -m "<message>"
If you want to add all changes made to tracked files & commit
git commit -a -m "<message>"
# or
git commit -am "<message>"
Amend or change the last commit message
git commit --amend
Amend and add new changes to the last commit
git commit -a --amend