how can I display only desired items?

[menator01]

Why the unnecessary loop on line 25? Dicts let you access items by key, so mydict[product_name] gets you the value associated with key product_name.

You are right.

#! /usr/bin/env python3

mydict = {
'predator': {
            'id': 1,
            'name': 'predator',
            'producer': 'acer',
            'category': 'laptop',
            'price': 1000,
            'stock': 5
            },
'monitor': {
            'id': 2,
            'name': 'monitor1',
            'producer': 'dell',
            'category': 'monitor',
            'price': 500,
            'stock': 10
            }
}

product_name = input('Enter name of product: ').lower()

if product_name in mydict.keys():
    print()
    text = f'Details for {product_name.title()}'
    widths = []
    for n in mydict[product_name].keys():
        widths.append(len(n))

    width = max(widths)
    print(text)
    print(f'-' * len(text))
    print()
    for item, desc in mydict[product_name].items():
        if len(item) < width:
            space = (width - len(item)+1)
        else:
            space = 1
        print(f'{item.upper()}: {" " * space}{desc}')
else:
    print('No product with that name')

Output:
Enter name of product: predator

Details for Predator
--------------------

ID:        1
NAME:      predator
PRODUCER:  acer
CATEGORY:  laptop
PRICE:     1000
STOCK:     5