Any answer to a question can be passed to survey via a link by adding additional URL parameter "q" to the survey's starting link.
Example:
The same survey is run in several countries and you would like to have an additional variable COUNTRY which would fill in automatically when sampling in different countries. In such case you need to create a single choice question COUNTRY at the beginning of the survey with answer options (e.g. 1=Denmark, 2=Norway, 3=Sweden), and make it hidden. Then in the live link there should be added additional tag ?q[COUNTRY]=1 for sampling in Denmark, ?q[COUNTRY]=2 for sampling in Norway, ?q[COUNTRY]=3 for sampling in Sweden.
If more answers of the survey need to be filled in automatically, each tag should be separated with & sign in the link.
Below is a link structure for different types of questions.
Single choice:
{your_survey_url}?q[{question_code}]={answer_code}
Multiple choice:
{your_survey_url}?q[{question_code}][]={answer_code}
Linear scale:
{your_survey_url}?q[{question_code}]={scale_value}
Open text:
{your_survey_url}?q[{question_code}_{answer_code}]={your_text} ({answer_code} - in this case it is usually "1" if not changed)
Single choice matrix:
{your_survey_url}?q[{question_code}_{row_code}]={answer_code}
Multiple choice matrix:
{your_survey_url}?q[{question_code}_{row_code}][]={answer_code}
Linear scale matrix:
{your_survey_url}?q[{question_code}_{row_code}]={scale_value}