Please follow below steps in creating internal discounts:
Click Home tab
Beneath desired season, click Setup
On right sidebar, click Discounts
Click Add new discount
For Discount type, choose Custom (internal only)
Enter Discount name and Default amount
Note: The amount you enter as the default amount will present as a suggestion each time you apply this discount, but you can choose the amount in each instance you apply it.
Click Save
Repeat the process until all desired internal discounts are listed in the discount library. Your discount(s) is/are now a part of your library and can be applied internally to new or existing orders.
Note:Even though custom internal discounts are created within the context of a specific season, these discounts are recognized at an organization level and the discount library will appear the same no matter which season's setup process it is viewed in.
Note: Internal Discounts can't be applied to Session Options Only.