If a user should no longer have access to your organization, you have the option of disabling that user's account or deleting; however, it's generally recommended that user accounts are disabled rather than deleted.
Deleting a user account prevents the user from logging into your organization and accessing any data, but it also removes that user from any objects they were assigned to via a user group, which may affect your reporting. Disabling an account prevents the user from logging in and accessing data, but the user is not removed from any assigned objects, thus maintaining your records.
Also note that deleting an account does not remove the user from your company database. If you require that one or more users are removed from the database, contact Resolver Support for assistance.