If you have purchased your domain from Shopify, your domain is hosted by OpenSRS, and that is where you will modify your DNS records.
To get your OpenSRS login credentials, you have to contact Shopify Support.
Step 1) Get your DNS values from Conversio:
From Outgoing Email Settings, enter your domain name under DKIM/SPF Authentication, to generate the 3 values.
Step 2) Login to your OpenSRS account from manage.opensrs.net.
Click on Modify DNS Zone to modify your DNS records.
Copy/paste the values provided by Conversio for all TXT and CNAME values in the corresponding fields.
Save and you're done!
Step 3) Give it some time! Please note that domain propagation can take 24-48 hours depending on your settings.
Still need help? Contact us at firstname.lastname@example.org