I have personally requested this over 5 times in the last 2 years. Our store is in the top 2% of all Shopify stores. They do not care.
Shopify has a lot of good things going for it, but they are lacking some of the most basic functions of a platform. Trying using their useless "edit" order feature. It is a joke.
This is a basic, critical feature. We have customers who need to track their orders in their accounts for a variety of reasons, if anything to track their warranty. If a customer forgets to log in to order, not having a way to link their order to their account inconveniences the business and the customers. It's also a basic feature that far more inferior sites (like BigCommerce) offer as a no-brainer. Customers who accidentally log in under one email address and wish to have their orders merged into the business account.... spouses or friends buying gifts for customers that should be under the customer's profile and not the person who isn't likely to buy again so that our customers can track their warranty or inventory their items... It's all very simple, no brainer features that should be offered at the FREE level at this point, never mind the Plus level.
I can hear the admins now, "But you can just force-password your site so they MUST log in to place an order".... that's well and good for some sites but almost laugh-worthy for something so niche that we sell. And people purchasing gift certificates for loved ones won't take the time to create an account just to purchase a gift card. To test this, I did a poll in our facebook community (3000+ customers) asking if I force-passworded our site to "remind people to log in so they can keep track of their order" would that help - and the poll was a resounding ABSOLUTELY NOT. In fact, more than half said that we would lose customers if their family had to create a password and an account to buy a gift certificate for them. The problem isn't our customers. The problem is not being able to true-up a problem with an order and an account on the backend, on a site where we are supposed to be "all powerful" and have "full control" in the year 2021.
My Plus rep played so shocked and confused that I asked about this feature, and stuck to this fake-shock so convincingly for the few weeks I interacted with him, it made me want to find where he lived and punch him in the face. Businesses need this feature to provide customer service. BASIC.CUSTOMER.SERVICE. At one point my exchange with him over his shock for such a feature was so upsetting, I typed a lengthy reply to him that ended with "I'm actually shocked I have to continue to list 8 reasons why this feature is critical, and if you don't understand it by this point, I don't think we need to speak again."
So here is the ridiculous thing we did to remind customers to log in to place an order they wanted tied to their account: we added an ANNOYING POP UP, not a call-to-action for a sale... but an annoying, "Don't forget to log in! We cannot retroactively attach an order to your account!" pop up. How absolutely ridiculous and sub par for a website we're paying thousands of dollars a month to have.
Please add me to whatever list exists to have my name added to the vote list for this feature.
There's a fundamental disconnect between Shopify and the reality of dealing with customers on the ground.
That disconnect is caused by gate-keeper support mixed with an unhealthy, Apple-like arrogance which leads to a lack of visibility on platform improvements.
The fact that Shopify doesn't use a proper customer database (as @Tony39 explained earlier) brings all of this into focus. It's a gigantic, deep black hole when trying sort customer issues.
Try running a successful pop-up sale with inpatient customers who dish out lip to your face, then walk off when things take too long or can't be done. It happens, it hurts and any Shopify developer who's experienced this would get it sorted quick.