7dd deletes the next 7 lines following the cursor. Holds the deleted lines in a buffer, available for subsequent pasting using the p command. 3dw deletes the next 3 words, starting at the cursor. Inserts text before the cursor. J Joins the next line to the end of the current line.
P Puts the contents of the buffer immediately before the current line.
Replaces the current character by the next character typed. R Replaces all characters that you type over, beginning at the cursor and ending when you hit the ESC key. 5s will delete 5 characters, starting where you are, and replace them with whatever you type. S 3S will delete 3 lines, starting where you are, and replace them with whatever you type. 3w moves 3 words forward.