As you probably know, Shopify will take care of hosting your online store, but it host your email. There are some free options out there, but here’s one simple way to have a custom domain for Shopify and then have custom emails using that same domain.
To achieve this, I need separate hosting for my emails.
Note: This process will involve editing your domain DNS records. If you are unsure, simply send these instructions to your email hosting provider. To access your DNS records, you will need to login to your hosting provider where you purchased your domain name.
Step 1. Go through the steps to assign a custom domain to your Shopify Store.
In summary; create an A record like so;
Then a CNAME record;
You’re done! This will assign your domain to your Shopify store.
Note: you will have to wait for the DNS settings to take effect. You can check by entering your domain name at; https://www.whatsmydns.net/ – and see if the Shopify i.p. address; 22.214.171.124 shows up for your domain.
Step 2. Find some cheap but reliable hosting.
Remember; you only need this for email so the hosting doesn’t need to be lightning fast.
Tip: Go for a dedicated i.p. address with your hosting if that’s an option (it should be). Shared i.p. addresses often get blacklisted by mail providers (Gmail, Hotmail etc) as someone on your shared hosting environment has been sending spammy emails. If someone on your shared server “dirties” the reputation of the i.p. address you are all sharing, it ruins it for everyone.
MX Record mydomain.com mail.mydomain.com
CNAME record; mail.mydomain.com [the i.p. address provided by your web host]
BONUS TIP: Setting up an SPF Record
Have you ever received an email that says something like;
firstname.lastname@example.org via serv124r5221.mccontrol.com ? –
In other words, the email is showing as being delivered via another server? This is because the company did not set up an SPF record.
Without going into too much detail, having an SPF record proves you own the email you’re sending and signals the mail server at Google and the like to not treat the email as spam.
Here’s how to create an SPF for Shopify so that when your notification emails go out they do not say they are “delivered via” another source. This is still done at your hosting provider, but this time it needs to be a TXT record.
v=spf1 ip4:[your i.p. address] +a +mx include:shops.shopify.com ~all
Edit the record above by adding your i.p. address in there. Be sure to take out the  square brackets.