This is a free template with 3 examples of using form fieldset-s in Bootstrap 4. Download it, customize it and use it as you like!
A form with 2 "fieldset"-s: "User's credentials" and "User's preferences".
A form with 3 "fieldset"-s: "First / Last name", "About" and "Preferences".
A form with 3 "fieldset"-s: "Current occupation", "Your address" and "Job preferences".