By default, git will use vi as a text editor, and @ShrubtheBub's answer is 100% correct to guide you into your first steps with vi.
You may however want git to open a more friendly text editor (say Notepad++ or VSCode ?) when git asks you to edit text.
There is a configuration parameter for that : core.editor
You can read this guide from the official git book, for example :
- here is a line to say "use notepad++" :
git config --global core.editor "'C:/Program Files/Notepad++/notepad++.exe' -multiInst -notabbar -nosession -noPlugin"
- to use VSCode instead, type :
git config --global core.editor "code --wait"
(taken from the vscode documentation)