What is a Quote Line Item?

Answer: ‘Quote Line Items’ is a related list on a quote.

Explanation:
A quote can be treated for an opportunity. For adding a Quote Line Item
to the ‘Quote Li ne Items’ related list, click on ‘Add Line Item’.
Then select any one price book. Then select any of the products
available in that price book. Modify the prices if required and
specify quantity for each product. A Line Item in the ‘Quote Line
Items’ related list is nothing but a product from the Price Book
selected for this Quote.