When sending a message that contains a link, you may want to pass some subscriber data along in the URL. You can do this using the Make URL safe option when inserting subscriber data.
Create a new message.
Add the URL you want to send.
Click the Insert Subscriber Data icon.
Select your attribute. Optionally, set a fallback.
Select Additional Settings > Make URL safe. Clearstream will percent encode subscriber data before sending the message.
That's it! Send or schedule your message and your link will safely contain subscriber data.