You can connect your TikTok Marketplace feeds with Shopify using AdNabu's Google Shopping Feed App
AdNabu's Google Shopping Feed App can connect your Shopify store to the TikTok feed with just a few clicks.
Follow the below steps and connect your TikTok feed:
1. Go to Marketplaces, and select TikTok Feed.
2. Select one or more countries, languages, and currencies.
3. You can customize UTM parameters like source, medium, and campaign.
4. Once you click on Enable and Save, a unique Data Feed URL will be generated for each selected country, language and currency.
5. Copy the URL and use it as a data feed URL in your TikTok Marketplace.
6. You can also click on the Refresh button to regenerate the Data Feed URLs.
Follow the below steps to add the above Data Feed URL to your TikTok Marketplace:
1. Go to TikTok Business Center, navigate to Assets, and select Catalogs.
2. Click on Add Catalog, and enter catalog details like name, default location, and default currency. 
3. Once your catalog is created, click on Add products in the created catalog.
4. Select the option Data Feed Schedule and click on Next.
5. Enter the Data Feed URL based on the currency selected.
6. Enter other feed details like feed name, schedule, etc., then click on Import.
The upload for all your products will start as per your selected schedule. Once the upload is completed, all your products will be added to your TikTok marketplace.
TikTok Marketplace Feed is available for Basic, Advanced, and Plus plan users.