Most common case is showing data from backend API and with ng-select this is extremely simple since you can bind directly to observable when using angular | async pipe
You can also set array of objects as items input
While array of objects is the most common items source, you may want to set simple array of strings, numbers, booleans
If you have simple use case, you can omit items array and bind options directly in html using ng-option component.
Selected value: {{selectedCompany | json}}
Selected value: {{selectedCompanyCustom | json}}