'Iteration' is simply repeating something.

Typically, in the computing world, it refers to some form of a looping
process within code. Worksheet functions have few iterative capabilities,
although it could be argued that various functions must do repetitive work
"behind the scenes" to achieve the single output that they provide. For
example, the SUMIF() function iteratively tests numerous cells for a
condition and adds values based on the results of those tests.

Within code, iterative actions usually involve loops such as For...Next
While...Wend Do...Loop and similar commands.

"Khalil" wrote:

What is iteration and how to use it; please advise

regards
Khalil