Quantity of a product on the order form

Good morning all
I have a concern. to define the quantity of a product on an order form, choose a number on the keyboard then click on the product. I have a customer who wants to increase the quantity of a product just by clicking on the product name several times.
example: if I click twice on the name of a product, the number changes to 2 and not that the name of the product appears twice on the order form.
please how to do it ??

Don’t thinknyou can by normal flow. However on ticket close/submission similar orders can be merged to qty lines, pretty sure by default.
Changing qty line would be by selecting the order line and +/- on top left.