How to generate unique number in each cell?

[Machme]

Hello I just new here and new in using EXCEL macro/VBA; can someone help me out on how to auto generate a unique number in each cell, after each entry of data in spreadsheet? Is there any formula or macro?

Thanks!

[protonLeah]

Why not just use the date and time?

[Machme]

can you post an example in applying it in particular cell? Let's say A1 cell automatically generate the date and time after entering an certain data in B1?

thanks!