Modes

Insert mode : (Where you can just type like normal text editor. Press i for insert mode)
Command mode: (Where you give commands to the editor to get things done . Press ESC for command mode)
Most of them below are in command mode

Commands

x: to delete the unwanted character
u: to undo the last the command and U to undo the whole line
CTRL-R: to redo
A: to append text at the end
:wq: to save and exit
:q!: to trash all changes
dw: move the cursor to the beginning of the word to delete that word
2w: to move the cursor two words forward.
3e: to move the cursor to the end of the third word forward.
0 (zero): to move to the start of the line.
d2w: which deletes two words. number can be changed for deleting the number of consecutive words like d3w
dd: to delete the line
- 2dd: to delete to line .number can be changed for deleting the number of consecutive words
  The format for a change command is: operator [number] motion-operator - is what to do, such as d for delete
  - [number] - is an optional count to repeat the motion
    - motion: moves over the text to operate on, such as w (word), $ (to the end of line), etc.
p: puts the previously deleted text after the cursor (Type dd to delete the line and store it in a Vim register. and p to put the line)
r: to replace the letter e.g press re to replace the letter with e
ce: to change until the end of a word (place the cursor on the u in lubw it will delete ubw )
ce: deletes the word and places you in Insert mode
G: to move you to the bottom of the file.
gg: to move you to the start of the file.
Type the number of the line you were on and then G
%: to find a matching ),], or }
:s/old/new/g : to substitute ‘new’ for ‘old’ where g is global
/ : backward search n to find the next occurrence and N to search in opposite direction
? : forward search
:!: to run the shell commands like :!dir, :!ls
:w: TEST (where TEST is the filename you chose.) . Save the file
v: starts visual mode for selecting the lines, and you can perform operation on that like d delete
:r: Filename will insert the content into the current file
R: to replace more than one character
y: operator to copy text using v visual mode and p to paste it
yw: (copy)yanks one word
o: opens a line below the cursor and start Insert mode.
O: opens a line above the cursor.
a: inserts text after the cursor.
A: inserts text after the end of the line.
e: command moves to the end of a word.
y: operator yanks (copies) text, p puts (pastes) it.
R: enters Replace mode until <ESC> is pressed.
ctrl-w: to jump from one window to another