a) Login to CPanel of your website
b) Search for Sub domains option and click on it
c) On this interface you should see existing subdomain if you have created any .
d) Now click on the Manage Redirection option next to the sub domain which you want to redirect
e) On the next step enter the URL (e.g.https://redirect.com) to which you want to set the redirect
f) Click on Save and you are done