The T-Shirt Size is a relative estimation technique used in agile projects. Rather than using a number of planning pokers, here, Items are classified into t-shirt sizes: XS, S, M, L, XL, XXL…
To create and configure the T-Shirt size custom field, you must be logged in as a user with Jira Administrator permissions.
Go to Settings → Issues → Custom Fields
Create a new custom field of type CFS - T-Shirt Size
Add name and description
Associate the field to the appropriate screens. You must associate a field to a screen before it will be displayed.
Click on 1 Context and click Create, edit or delete contexts on the dialogue.
Click Edit custom field config.
Set description for T-Shirt values.
Steps 5, 6 and 7 are not required. You can use the default values that are set in the app configuration screen.