If you navigate to https://duckduckgo.com/lite/ or https://lite.duckduckgo.com/lite/, type your query in the form input field, you are using POST. If, OTOH, you were to type your query into the address bar, e.g., https://duckduckgo.com/lite/?q=xyz then you are using GET.

   curl -Huser-agent= https://duckduckgo.com/lite/?q=xyz|grep result-link

   curl -Huser-agent= -dq=xyz https://duckduckgo.com/lite/|grep result-link