When starting on Sitecore Forms functionality, one must carefully consider validation and security requirements for each individual client based on their organizational standard for security and how that affects form behaviour.
For those who are not familiar with the importance of client side AND server side validation when it comes to user inputs through the use of forms, organizations can easily expose themselves to risks. Let's use string length validation as an example.
Client Side Validation
Sitecore Forms validates field inputs on the front end using the jQuery Validation plugin. Content authors can select front end validations in the Forms editor.
Form Submit Actions
On form submit there are various built in actions that come out of the box with Sitecore Forms. Let's use "Save Data" as an example.