Hey there VeF!
Genevieve from Shopify here :)
In terms of apps, MailMunch allows for the addition of custom fields quite easily :) I tested this out and was able to add text fields for 'country' and 'date of birth' to the newsletter signp form, like so:
You can get that app here: https://apps.shopify.com/mailmunch
I can also confirm that Klaviyo can add the fields you need to the newsletter signup form, with a little bit of custom coding. They have specific guides on how to add these fields:
Alternatively, you can customise the Shopify newsletter signup form to collect this information:
Hope that helps!
I know this is an old post, but you may still be interested.
Our Happy Birthday app (https://apps.shopify.com/happy-birthday-email) allows Customers to sign-up to a Birthday Club on the order status page once they have placed an order. The app will then send the Customer an email containing a discount on their Birthday.
It also has the ability to sign new Customers up to the Birthday Club directly from a store's existing MailChimp sign-up forms, as long as the form contains a Birthdate field. The feature can enabled upon request, it's really quick to enable and is a great way to build your Birthday Club.
Please just let me know if it's something I can help you with!
You can install Aitrillion.com . It has the features that you are looking for. It is all in one app with integration which will prove to be best in terms of reaching your customers and that would avoid customers spamming. It has powerful customer segmentation, custom drag and drop email editor, AI-enabled email scheduling, which can help you to send targeted emails, other than that it also has workflow automation. You can use this platform to send email based on their buying behavior along with all these features, it also has prebuilt workflow and templates. Its email marketing is integrated with reviews, loyalty reward program. You can check it out.
You can contact to their support. They provide free setup. Also, you can schedule a demo to learn more about the feature.