Yelp app is a useful travel app that provides user submitted reviews and recommendations for local businesses.
Yelp does not have the direct delete button/link, but you can use the form in their contact page to request account deletion.
If you would like to delete your yelp profile on the web follow these steps:
STEP 1. Login to your yelp profile using your username and password
STEP 2. After login, click the following direct link to delete your yelp account.
In this page you have the option to delete your yelp account.
However you can read more about account deletion tips at the link below: