You can create a new page and use following shortcode bellow to display alert create form and alert list. user can create alert and delete, can pause anytime.
Shortcode:
[job_bm_alert_job]
Parameter : No parameter for this shortcode
How its work?
Once you activate the plugin one your site it will create a table ( job_bm_job_alerts
) on wodpress installation database, and wp_schedule_event
add corn daily and weekly on your WordPress server. When user create an alert via form it will keep record on that table and when corn job fire it will execute alert with respective option save by user, and sending an email to user email address.
Output: