You can sign up for a business email account with Integrate Tax, to get custom domain based email address like admin@integratetax.com.
Generally, if you want to sign up for a domain based account, make sure that you have permissions to access the DNS Manager page of the domain. The entire Email Hosting Process is explained in this help page.
The personal users, who need @(companyname).com accounts, refer the image below and click the Sign Up link below the pricing plans listed for business. The personal users need to choose a username. You need to provide a contact email address, at the time of registration.
You will receive a confirmation email to the contact email address you have provided. You will be able to send emails, only after you confirm your account.
The Organization Admins create users, from the Control Panel and provide an email address and password during account creation. During the first sign in, the users should provide their email address and the password given by the administrator. The users can change their password, if required from 'General Settings'.
Mail allows you to utilize your Google/ Yahoo/ Facebook credentials, to create and account in Mail, access Mail Services using federated Sign In. You would be asked to choose a Mail username, when you use a federated Sign In for a personal account. When you use federated Sign In, you will be able to access only the webmail for accessing your email account, since you will not have a specific Password.
In case you want to access your account via POP/ IMAP or Active Sync or want to enable Email Forwarding for your account, you need to generate a Password for the account. Follow the steps below to generate your Password.
Supports SSO and all the Applications share the same credentials and the same profile settings across the services. Hence all the settings can be accessed and changed .
Alternatively, some basic profile settings can be updated from the General Settings in Mail. You can set the default language in your profile. Based on the language you choose, the Mail interface will be available in the language.

The following languages are supported in Mail.
The users can change the Language from the General section in Mail Suite.
Steps to change the Language
The changes will be reflected after the page is refreshed.
The users can change their Password from the General section in Mail Suite.
Steps to change the current Password
The time in the email is listed based on the Timezone set for your organization.
In case the emails are displayed with incorrect or irrelevant times that do not match your current time, it is possible that the Timezone chosen is incorrect for your account. Follow the steps below to choose the correct timezone.
Steps to choose the correct Timezone
The Primary Email Address is the email account that is linked with your Email Account. For users, the Primary email address will be used for verification and Password reset purposes only.
Steps to change the Primary Email Address