After seeing a lot of different solutions that companies are using to meet these requirements, I decided to make my own using Microsoft Flow, Forms, Teams, SharePoint, and Outlook. Interested candidates fill out the form that was created in under 20 minutes using Microsoft Forms. When they submit the form the information gets added into fields in a SharePoint list item. A discussion message is then posted in a HR Team channel with a link to the new candidate SharePoint item. If an email is entered into the Referrer Email field, the person will be sent an approval email to approve or reject the candidate's referral. The approval response will then be posted in a second message in the HR Team channel.
Prior to creating this Flow you will need to have: A new candidate form created with Forms, A SharePoint list that has fields to correspond with your form, an HR Team in Teams
Click here for detailed instructions on how to create the Flow.