Matt here from the Shopify team. Although the Product Reviews app doesn't have this feature quite yet, you might want to consider the Yotpo Social Review App. It allows your customers to leave product reviews, and also lets you send out review request emails to your customers that they can answer directly from their inbox:
Hope that helps!
Auto-email is probably one of the most important features for review apps. As Matt pointed out - there are several alternatives to Shopify's reviews app. Since you're in the fashion business - I'd love you to check out Loox - Fashion Reviews (https://apps.shopify.com/loox-fashion-reviews). ;
Loox automatically collects rich visual reviews from your customers, shows your visitors how items look, fit and feel on various body types, and helps visitors overcome size & fit concerns.
Hope this helps!
You should give Judge.Me a try:
Laser-focus on Shopify, very affordable, and absolutely the best support you can ever expect. It will be part of our next update.
Check out Shopify's Products Review app which is free. It is just a review app but when coupled with the Addon, it automates the process of sending emails to your customers to get them to leave their reviews directly inside the email, after X days of their purchase or even only after fulfillment has been done.
Also tons of other features.
Fully customizable to suit your branding and price point doesn't hurt at all (: