Referral mechanics can vary by firm and recruiting system. Some candidates receive a referral link or confirmation; in other cases the employee action happens internally.

If the person said they submitted it, avoid repeatedly asking them for proof unless you genuinely need a link to complete the application.

Follow the application instructions you received. If there is ambiguity close to the deadline, a short recruiter question is more useful than submitting duplicate applications.

Mine never sent a confirmation. Recruiter could see it though.

I got a special link, so apparently it varies.