Substitute is to note a products in the system is the equivalent of another product. Either product can be purchased as a replacement for the other product.
1. Please go to the Products -> SUBSTITUTES -> +New Substitute and Choose Product for which substitutes will be specified
2. Now, Choose a Substitute Product and click the Add button.
You can choose more than one substitute products
To see Substitutes section on the Sales order page you need to enable the setting
Setup ->UI / Feature Settings -> Sales Order Item Form -> Show Substitute Products
To see Substitutes section on the Invoice page you need to enable the setting
Setup -> UI / Feature Settings -> Invoice Item Form -> Show Substitute Products
You can also display the costs related to substitutes products
Setup -> UI / Feature Settings -> Company -> Show costs with substitute levels
To use the substitute product you need to choose the main product in 'Product or Service' field. The list of substitute products for the main product will be displayed in the Substitutes section. Click the Select button to choose the substitute.