There is an default Mail app in iOS devices. This post include the steps on how to integrate your email with the Mail app.

Step 1
In your iPhone, got to Settings > Accounts & Passwords.

Step 2
Select Add Account.

Step 3
Select “Other”.

Step 4
Select “Add Mail Account”.

Step 5
Insert your name, email, and password. Click “Next” when done.

Step 6
Insert accordingly,
Host Name is start with “mail.” and following with your website address.
eg: mail.yourwebsite.com
Username is your email address.
And password is your password to your email address.
Input the same for both Incoming and Outgoing Server

Step 7
Make sure “Mail” is selected, click “Save”.
Now you can send and receive email from your iOS device.