1. how to delete text inside a double quote and go to insert mode? - c+i+"
2. how to move to the end of line? - $
3. how to delete everything before "x" character and go insert mode" - c+t+x
...
EDIT: updated mistakes.
ciw will change inner word, ci" will change inside quotes
> 2. how to move to the end of line? - "g_"
$ is generally used as the noun object to represent "end of the current line"
> 3. how to delete everything before "x" character" - "ctx"
dtx would delete everything before the next x. ctx would delete and then put you in insert mode :)
1. how to delete text inside a double quote and go to insert mode? - c+i+"
2. how to move to the end of line? - $
3. how to delete everything before "x" character and go insert mode" - c+t+x
...
EDIT: updated mistakes.