Hey @HelenCK, welcome to the HubSpot Community and thanks for your post!
In the standard quote template editor, design changes are limited to the available branding/layout/module options, so extra CTA buttons like “Need more time” with a required explanation field aren’t supported out of the box.
For that experience, you’d need a custom quote module added to the quote template. That’s the best route if you want both tighter styling control and a custom response flow for the buyer.
Here are similar threads that might help:
I’d love to have the perspectives of our Top Experts: Hi @HubDoPete, @Anton and @nickdeckerdevs1 do you have other suggestions to help @HelenCK, please?
Thanks so much and have a wonderful day!
Bérangère