P.S. I want to add say a column of 30 phone numbers or emails and check if
any is duplicated in A to Z.

"Parker" wrote:

I am using excel as 'a diary' with worksheets A to Z as well as a few othre
sheets after Z which are labelled 'sheet', 'sheet1' and 'sheet2'.

In sheet if I enter a phone number or email address, hoe can I check if it
exists anywhere in sheets A to Z ?