How can I add an extra field to my newsletter sign up form?

[kiradullard]

Hi all,
I'm trying to add an extra field to my newsletter sign up form.
Its at the bottom of this page 
https://abbie-james.com/

The theme I'm using is Ira
https://themes.shopify.com/themes/ira/styles/active?surface_detail=ira&surface_inter_position=1&surf...

Anyone know how I can add an additional field for people to add their names

TIA