Hi @sajinshaji ,
I did a test for your reference.
In my scenario:


["'", "!", "@", "£", "^", "=", ",", "%", "[", "]", ";", "~", "?", "<", ">", "|", "u0001", "u0007","$","#","&"]
range(0, length(outputs('String_To_Modify')) )
if
(
contains(outputs('Unwanted_Characters'), substring(outputs('String_To_Modify'), item(), 1)),
'',
substring(outputs('String_To_Modify'), item(), 1)
)
join(body('Select'), '')Best Regards,
Sunshine Gu