Linking multiple stores
When you have multiple related ACF installations, like multiple language shops, shops for different regions, or shops for different environments (test, staging, live), you can link your ACF installations together for easy management of custom field definitions.
Choose the store, you'd like to use as the "master store" and from that shop's admin side menu, click the "Settings" button to open the settings dialog and go to the "Stores" tab:
In the "Linked stores" area, type one of your related stores' ".myshopify.com" domains (just type the part before .myshopify.com) and press Enter. For each linked store, you are required to input that store's API key to verify your access. You find your other store's API Key in the "Plan" tab, but of course from its own Settings dialog. When you enter the correct API key for the linked store, you'll see the domain shown in green like in the example above. Add more stores in the same manner. Then select your synchronization option.
While the "Complete" synchronization option is recommended, only select this, if you'd like field definitions to be mirrored 100% across your linked stores. The "Partial" option is safer (it won't delete field definitions), but may lead to duplicated section definitions, if these were set up manually prior to a sync (only applies to sections created before September 20, 2020)
Click Save and your linked stores will be ready for easy synchronisation of custom field definitions.
You can mix and match the linking as you please, so for example store A links store B and vice versa or store A links store B + C and store B links store D. Plan this carefully to avoid confusion.
Field definitions can be manually synced to any or all of the linked stores. When you have set up linked stores, the Save button for field definitions will expand with a drop-down menu to the right, allowing you to choose additional targets of your Save operation:
Each linked store can be selected individually or you can select to sync all linked stores in one go. If you opt for only saving changes to the current store, you can always come back and sync to the linked stores.
No matter the chosen option, any changes will always be saved to the current store
Warning: depending on your synchronization settings, syncing field definitions is potentially a complete sync. Any fields already defined for the target store(s) and not mentioned in the set of fields being saved, will be deleted.