We need to send emails two times a year (1/3 and 1/9) every year. Is it possible to make a cron expression for that or do I need to make two functions?
Yes! I think that would be 0 0 0 1 3,9 *
I use this website to try expressions: https://cronexpressiondescriptor.azurewebsites.net/
The cron library Azure Functions is using: https://github.com/atifaziz/NCrontab