For your Apple, you probably use Apple Mail. Below is the description for Apple Mail for version OS X - MacOS 10.12 Sierra.
Open Mail and click Mail > Add account...
at the top of your screen in the menu.
At the top of your screen, click on Mail and in that row click on Preferences...
In that screen, click on Accounts and then on the + sign at the bottom left
You will see the screen Choose a Mail account provider, tick Other Mail account... and click on the Continue button
You will now get to Add a Mail account
Fill in your full name here (that's as recipients will see it on screen), your e-mail address and your password.
Then click on the Log in button.
In the following screen, fill in:
your e-mail address
and at Username again the full e-mail address
Type of account: IMAP (in this example)
Incoming mail server: mail.jouwdomein.nl (fill in the data (host name) provided by your webhoster)
Outgoing mail server: mail.jouwdomein.nl (fill in the data (host name) provided by your webhoster)
Click Log in.
In the next window you have the choice of what you want to link to your account, in this case we only tick Mail and not Notes (notes) . When you're done, click the Finished / Done button.
Your mail address has now been added to Apple Mail.