Customisation in Item for Drop down Field

We need to Customise in Item and create a new Field.
Like as and Example, need One dropdown link with data for COUNTRY TYPE & another Link with data for all the CITY of all the COUNTRIES.
After Selection of the Data from single COUNTRY only data linked with that COUNTRY should be shown in CITY and not other in that datatype.

Can someone help us with this query.

Check out the excellent documentation here, it’ll help you get started! :wink: