Hi Riya,
You can use Regular expressions to match on certain characters.
Regex for Special Characters:
[!@#$%^&*()_+{}\[\]:;<>,.?~\\/-]
Regex for Special Characters and Alphabets:
[!@#$%^&*()_+{}\[\]:;<>,.?~\\/-a-zA-Z]
You can use these in the validation rules of the enitity or inside a microflow with the function isMatch().