how to add script in jira while creating an issue

[aman bansal]

I am creating issues like label name should be only alphabet and min and max limit should be 1 and 40 so how should i embed the script in that 

[Yogesh Mude]

HI @aman bansal 

Welcome to the community

Can i ask you...what do you mean...

How to add a script in Jira while creating an issue?

I am creating issues like label name?

To which field you want to apply restrictions for the alphabet should be min and max 1 to 40?

[aman bansal]

for text field