Where are my custom fields stored?
All custom field definitions as well as the values you enter are stored as metafields within your Shopify store. This means that you never rely on any third-party system but can trust Shopify to keep your data safe. Metafields are an integral part of the Shopify platform and provide secure storage for your data. One exception: due to restrictions in Shopify's API media uploads are stored externally on a secure Google Cloud server with daily backup (the reference to the media is stored in a Shopify metafield)
Will this work in my high-traffic Plus store?
Without a doubt. Firstly, retrieval of metafield values (where your custom fields' values are stored) is done by Shopify within Shopify's infrastructure, so it's no different from any other piece of content you create inside Shopify. Secondly, media uploads (with or without image resizing/cropping) are served directly via a global CDN optimized for delivery speed with very low network latency. Our CDN is serving more than 3 billion requests per month and there's room for yours as well
How do I show my custom fields on my storefront?
Using Liquid together with Shopify Metafields, you can easily integrate the values into both your design and notification templates. Our Help Center shows examples covering the supported field types as well as tutorials to work with our various features
Can I use ACF to manage existing metafields from other apps?
Absolutely. Just as well as ACF lets you define fields in discrete namespaces to keep it from updating metafields from other apps, you can also use it to handle metafields defined by other apps and migrate to ACF easily. ACF features an easy-to-use wizard to find existing metafields in your store and will automatically reuse any existing values once definitions are in place
The app installation requests managing of my store? Really?