Expert opinion on Types of validation

Good Day!

Can any one give an expert opinion as to how many types of Form validation one hase to take care when developing a form where an user will input the data.
I am interested in all possible important validations as
– client side,
– server side,
– Security,
– check during input (example user may type Arati’s instead of Aratis and similar
type of other checks which backhand or other language will not permit….etc

Thanks to you all
Arati