hi,
On sheet 1, the first column has the customer id# and other columns have
other details of that costumer(like: email, fax...)
On sheet 2 , the first column has the customer id#(doesn't have all the ID#
that sheet 1 has) and other columns have other information.

what can I do so it will look at each customer id# on sheet 2 look for for a
match on sheet 1 and add those additional columns from sheet 2 in that same
row on sheet1.
Please provide me the formula and explanation of the formula.
im unexperienced with this and need to do this on a very large sheet with
lots of data.
thank you.

example:
Sheet1:
CusID Phone Fax
1 XXX XXX
2 XXX XXX
3 XXX XXX
4 XXX XXX

Sheet 2
CusID Adress zip
2 XXX XXX
4 XXX XXX

MY result will be:
CusID Phone Fax Adress Zip
1 XXX XXX
2 XXX XXX XXX XXX
3 XXX XXX
4 XXX XXX XXX XXX

Thank you