Differences between in order to / as to / to / for

in order to do something


with the purpose or intention of doing or achieving something


She arrived early in order to get a good seat.
In order to get a complete picture, we will need further information.


AS TO
as to something | as regards something


used when you are referring to something
As to tax, that will be deducted from your salary.


TO 
5 used to show something that is known or reported about a 
particular person or thing


The house was said to be haunted.


FOR 
10 in order to obtain something


He came to me for advice.
For more information, call this number.