Zoho Mail Forever Free Plan
Zoho Mail - 'The Forever Free Plan' - is currently available in the US, EU, and India data centers only. Your IP address determines to which data center you are allocated. For example, I am in UK, and have been allocated to the Amsterdam (The Netherlands) data center.
Go to: https://www.zoho.com/workplace/pricing.html
Scroll down towards the end of the page:

Click on the 'Sign Up now' to proceed. Because I'm in UK, I've been directed to the zoho.eu sign up web page:

At this point, you need to choose the 'Business Email' option, to be able to use your own domain. The 'Personal Email' option only offers a zohomail email address.
Complete all required fields, including your 'mobile number' to proceed.
Once all is completed, you're allowed to use only one own domain, but can create up to 5 users (5GB storage per user) for that domain.
As with any new provider, it takes time to become familiar with the UI, set up the domain DNS records, users, etc.
