Myshopify is not a scam, it is legitimate. It is owned by Shopify, which is a complete e-commerce platform that lets people start, grow, and manage their businesses. In other words, it allows you to create and customize an online store. But, although Myshopify is legit, there are unscrupulous people who are using it to create fake stores used to ripoff online shoppers. The good thing is once those fraudulent stores are reported to Shopify they are removed.
Stores on Myshopify use the following domain or website name format - [YourStoreName].myshopify.com, where [YourStoreName] is the name of the store that the owner chooses to use. Or, store owners amy use their own domain or website name that they have purchased or registered elsewhere.