You have two options.
1. You can do this by running a
Windows Task Scheduler. It is nothing but one
Window or
Console App, which will be scheduled in your Server. Inside the app, write you email sending code.
You can select the
Time(when to run) and
Frequency(when to repeat it again) for the
Scheduler.
2. Refer -
How to run Background Tasks in ASP.NET[
^]. You can use
Azure WebJobs. If you don't have
Azure, then go for the other
Background Task managers mentioned by
Scott in his blog.