Hi ​@fvdk, 

thank you for reaching out here :-)

Personio has a Surveys app which is quite handy - but at the moment it can be only used for employees not for applicants. 
In your case you could use another tool to create the survey and add the link to the email template you are using when sending rejection mails to the candidates. The same could be done for after the recruitment process. 

I can well imagine that other users would also find this interesting.
Therefore, I recommend that you submit your feedback directly in your Personio account using the "Share Feedback" function. This way, your feedback will go straight to the relevant product teams.
You will be informed about product updates either through our article "Personio Product Updates" or via an in-app notification.

I wish you a great day!
Best regards
Roman