Thank you for getting in touch here in the Shopify Community.
I understand you would like to obtain your merchant ID, however, you're unsure of how to go about this. Our support team can retrieve your merchant ID for you, please note that this can only be requested by the account owner on file.
In order to get in touch with live support, you can do that byvisiting this page here. As we are unable to look into account specifics from the forums here ourselves, this would be the best way to proceed in getting your required info.
Aside from the above, how is business going? Is this your first store? I would love to hear more about your business goals and plans!
Since this is the next step, I've marked this reply as the solution for the benefit of others who may discover this topic.
Moira | Social Care @ Shopify - Was my reply helpful? Click Like to let me know! - Was your question answered? Mark it as an Accepted Solution - To learn more visit the Shopify Help Center or the Shopify Blog