We have our complete documentation on setting up subscriptions in a store:
How to set up Subscriptions in your store
Currently, enabling subscriptions for a SKU is done in the SKU’s “advanced settings”:
More specifically, in the attachments attribute by checking the checkbox related to subscriptions:
So how do you configure this for all products in bulk?
For that, you don’t need to go into each SKU individually to make the change — it can be done via spreadsheet. Just go to:
Catalog > Import and Export
On this page, you can select the fields to be exported. The SKU ID and Product ID are required, and you’ll need to include the Attachments field:
Then click Export to Excel — the download link will be sent to the selected email address (check your spam folder if it doesn’t arrive):
Once you’ve downloaded the spreadsheet, simply replicate the subscription for the desired SKUs and save:
The import should be done in the same module, now switching to the “Import” tab:
There you’ll be able to select the updated file and Import it:
I hope the information in this topic has helped you understand how to carry out this type of configuration. If you still have any questions, feel free to ask here! 
Júlia Fagundes
Field Software Engineer | VTEX