This post has been tagged as "server". Are you sure you are on Jira server and not on Jira Cloud?
If your Jira URL ends with "atlassian.net" you are on Cloud and you could contact Atlassian support to ask why you're not getting the email.
Otherwise you are on server and you will have to ask your Jira administrator to reset your password. There can be many reasons why you are not getting an email.
Ok then you're definitely on Jira server.
You can only get a password reset email if you configured an outgoing mail server.
Are you the admin of that Jira instance?
You can set an admin password with the recovery method described on Restore Passwords To Recover Admin User Rights
This involves setting a JVM property and restarting Jira.