To do this, perform the following steps:

1. Add a short answer question in your survey.
   
2. Type in a question name (Lead ID).
   
3. Select Prepopulate answer.
   
4. Type in a parameter (e.g.: 'a') in the URL Parameter box.
   
5. Click Save.
   
6. Navigate to crm.zoho.com, then click the Settings icon.
   
7. Click Setup in the list.
   
8. Click Zoho and select Zoho Survey.
   
9. Click Get Started Now and select Configure Current Account.
   
10. Click Save.
    
11. Click Setup in your CRM account.
    
12. Click New Template in the Templates section.
    
13. Click Select Module, and click Blank Template in the Leads section.
    
14. Create the email body and paste the survey URL by copying it from the Launch tab.
    
15. Type ?a= and type the # symbol at the end of the URL. Merge tags will be displayed.
    
16. Select the Lead ID. For example, if your survey link is something like this, https://survey.zohopublic.com/zs/deB0fw, after appending the parameter, it becomes https://survey.zohopublic.com/zs/deB0fw?a=${Leads.Lead Id}
    
17. Select the URL and click the Create Link icon.
    
18. Type in a title and click Save.
    
19. Send the template to the leads for them to answer the survey. The Lead ID will get prepopulated within the short answer question.
    

Read more here.