Manually assign  products to city

Assign Product: You can assign product to single/multiple cities from admin panel go to Catalog => Products =. Edit the product you want to set delivery city =>Click on Links Tab and find here 'Enter Delivery Cities:' => Now you can check single/multiple cities.

Bulk assign product to city by category wise

Bulk Assign Product: You can download/export already added products data by category and upload to single city or multiple cities from admin panel go to MultiCity => Major City => on top right hand side click on "Assign Location to Product" button. First Export and then Import. Check screenshots for more info.