How do I loop through worksheets and apply same function using for loop?

Hello, I'm new to VBA and am trying to learn it. I've written this function to try to loop through some worksheets within the same workbook and add a column to update the week notated as 'ww' based on the cell to the left.

I'm having issues with the For loop where it's supposed to loop through the defined sh1 to sh3. How do I declare the sheets to loop if using sheet.("sh"&i) does not work for the For loop?

The bold part is where I receive the debug error.
"Run time error: 9
subscript out of range"

I'm largely unsure of what I'm doing and experimenting a lot. On the side not, is there any good online learning courses that I can use to grow my knowledge on VBA?

Please Login or Register  to view this content.

are you sure you want a function and not a subroutine?

here is another way you could do it

Please Login or Register  to view this content.

Hello, I've copied and pasted your codes. I'm not sure why it's returning with the error that the variable 'ws' is not defined. I'm assuming that ws refers to work sheet, do I need to define what ws is? And to call a sub I can just use

Please Login or Register  to view this content.

right? Provided that I listed the subroutine as

Please Login or Register  to view this content.

. Thank you so much for helping me, I'm still trying to figure my way around things.

#Edit_1: I realized that yes, I have to declare ws as an excel worksheet.

Please Login or Register  to view this content.

oops that was my mistake leaving the declaration of ws out...i have inserted it now