First off, congratulations on opening your store! Before launching, did you get a chance to review our "Essential Shopify Store Launch Checklist"? This is an excellent resource that'll help you ensure you've completed all the necessary steps before you start selling.
In regards to which apps you should be using, this totally depends on what you need the apps for. Based on the title of your forum post, it looks like you may be searching for apps to help with shipping and collecting taxes. Is there a reason why you're considering an app for this? Are there any specific features that you want to add to your store that aren't available in our built-in tax settings and shipping settings?
I'd love to hear more about the types of features you're looking to add to your store and which apps you're considering! Feel free to respond here and let me know; based on your specific needs, I'd be happy to share some options with you.
Julie | 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