How to make unique instagram username

This plugin allows you to Restrict a particular or certain username, email addresses or symbols,
or email from specific domain names in the form registration when registering for your site
and you can allow to use a certain language (arabic cyrillic latin &#;)
or all languages and characters and symbols, you can also control and modify all errors messages
and allow certain characters (Symbols and characters accented as é û),
and allowing you to change the author slug (defaults to the username of the author),
and you can control and adjust all settings from the plugin settings page in admin Panel.

and here is all plugin settings in admin Panel:

• enable/disable the plugin
• disallow to use the spaces in username
• disallow to use only numbers in username
• disallow all characters (Symbols) in username
• disallow characters (Symbols) permitted by wordpress in username: @ &#; .

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• allow certain characters (Symbols and characters accented as é û)
• restrict certain email addresses
• re