Basic Inputs
Find helper text here for given textbox.
email@pixinvent.com
Sizing Options
                                                For different sizes of Input, Use classes like .form-control-lg &
                                                .form-control-sm for Large, Small input box.
                                            
Horizontal form label sizing
                                                Be sure to use .col-form-label-sm or .col-form-label-lg to your
                                                <label>s or <legend>s to correctly follow the size of
                                                .form-control-lg and .form-control-sm.
                                            
Floating Label Inputs
                                                For Floating Label Inputs, need to use .form-floating class & add attribute
                                                disabled for disabled Floating Label Input.
                                            
File input
Input Validation States
                                                You can indicate invalid and valid form fields with .is-invalid and .is-valid.
                                                Note that .invalid-feedback is also supported with these classes.
                                            
Input Validation States with Tooltips
                                        .{valid/invalid}-feedback classes for .{valid/invalid}-tooltip classes to display
                                        validation feedback in a styled tooltip.