You can customize your invoice line item view from toddler sizes to 6XL.
Head to My Account > Customize Your Line Items to select which columns you'd like to show in your invoices.
Any changes here will change the line item view for all invoices in your account
Customizing Sizing Options
At this time you are not able to customize what sizing options are available. We suggest adding that size to the description and populating the QTY box: