Create a private app for Shopify you can follow these steps:
1. From your Shopify admin, go to Shopify Apps.
2. Click Manage private apps.
3. Click Create a new private app.
4. In the App details section, enter a name for your private app and a contact email address: Shopify uses the email address to contact the developer if there is an issue with the private app, such as when an API change might break it.
5. In the Admin API section, select the areas of your store that you want the app to be able to access.
6. If you want to use the Storefront API, then select Allow this app to access your storefront data using the Storefront API.
7. When you're done, click Save.
After you've found an app that you want to use, you need to add it to your store. Then click the related install link. After you click the install link, you need to authorize the app in your Shopify admin. At this step, you receive a warning that the app isn't from the Shopify App Store. This doesn't necessarily mean that the app isn't safe to use. However, the app has not been through the verification and approval process that's required for apps that are listed in the Shopify App Store.
Open an app in Shopify
1. From your Shopify admin, go to Apps.
2. Click the name of the app that you want to open.
Wish you find the optimal solution for yourself soon!