This tutorial will work only if you have parked your premium or free domain from a domain registrar at 000webhost under the "Set Web Address" page. It will only work if you are using nameservers, not the CNAME record.
Firstly you should head into 000webhost.com and login
Once logged in "Manage Website"
Now hit "Set Web Address"
Find your domain on the list you wish to use GoogleMail with
Click "Manage" then select "MX Record"
You'll see this screen hopefully
Hit "Set to Google MX servers"
The page should change now - click save!
Now the to head over to GoogleMail to setup your domain there!
Choose your site name
Choose your location
Provide a contact email
Select you have a domain
Type in your domain name
Choose your name
Choose your administrator login email and a secure password
Share away if you want
This may appear, solve it.
If you want more email addresses simply set the users up now.
Add their names and emails and save them
Send out confirmation emails to you/your users
Add a personal message to your team if you want.
Now you need to verify sometimes you own the domain, simply upload this small piece of code onto your domain.
Else you can download a .html document and upload that to your site instead if you feel you don't want to insert the code into your index page.
Upload the html file to your public_html folder
Now the next few steps you can skip because we've already set the MX record in 000webhost.com because we have pointed our nameservers to 000webhost.
You may see this message until Google sees your verification of ownership i.e. meta code or .html file etc and until it sees the MX record correctly.
Once this has confirmed you own the domain you will be able to login to GoogleMail with email@example.com and your password and send + receive emails on GoogleMail using your own domain!