Im not sure of the Indirect way but this will work
=IF(LEN(A1)=1,"000"&TEXT(A1,0)&".HK.",IF(LEN(A1)=2 ,"00"&TEXT(A1,0)&".HK.",IF(LEN(A1)=3,"0"&TEXT(A1,0 )&".HK.",IF(LEN(A1)=4,TEXT(A1,0)&".HK.",""))))

"Eric" wrote:

Does anyone have any suggestions on how to set the value using Indirect
function?
I would like to change the 4- digit + .HK, the maximum digit is 4-digit.

There is a given number 5 in cell A1, it should return 0005.HK. in cell B1
There is a given number 941 cell A1, it should return 0941.HK in cell B1
There is a given number 2388 cell A1, it should return 2388.HK in cell B1

Does anyone have any suggestions on how to do it?
Thanks in advance for any suggestions
Eric