Help making a line item property mandatory before adding product to cart

Shopify Discussion
3

Thanks so much!

Here it is :

https://3nl26d7d07ztsby9-45398425759.shopifypreview.com/products/along-for-the-tide-wedding-invitation-set-trial-set?_pos=2&_psq=along+with&_ss=e&_v=1.0