I am creating custom checkout using draft order api & when customer complete order & reach thank you , continue shopping link is not visible .
while on same site if I do shopify default checkout , continue shopping link show on thank you page .
Is there any parameter we need to pass in draft order api ?
Well I got the answer by self 
.. I am writing this to those who are also looking for same :-
We can write below code in settings → checkout → Additional scripts
a.step__footer__continue-btn.btn { display: none;} .custom_thank_shipping{position: absolute;color: #fff;background: #197bbd;bottom: 20%;padding: 10px;} @media(max-width:767px){ .custom_thank_shipping { position: fixed; bottom: 0; padding: 13px 0; z-index: 999; width: 100%; left: 0; text-align: center; } }