I am not sure I understand your question.
Vim (or vi) has only two modes: insert text or command.
You start in command mode and press 'i´ (insert) to start inserting text.
When you are done, press escape and you go back to command mode.
When in command mode, you use simple, one letter commands to manipulate text or ':' command for more complex operations.
In command mode, vi (or vim) behaves almost like a programming language: you can combine one-letter commands.