Hi @Farhad Hosan, 

Welcome to the Community and thanks for sharing your question with us! 

Yes, you can send a campaign without integrating with your ecommerce store. You will need to manually upload your list of subscribers you want to send to, as they are not automatically syncing with your Klaviyo account via your store. I would ensure that your customers have confirmed that want to accept marketing from your brand before you send as to not negatively impact your deliverability i.e. people not opening your emails or going to the spam folder. 

I would encourage you to investigate our documentation on  integrating your ecommerce store with Klaviyo, as well as on the Community itself as there are huge on the benefits and advantages from integrating the two. The more software you integrate with Klaviyo, the more data will be in your account that you can use to further target your business' marketing goals and make data-driven decisions.

Additionally, I’d recommend checking out these resources to help you get started with Klaviyo! 

• Email Campaign Schedule and Send Options
• Getting Started with Klaviyo - Academy Course
• Intro to Email Design - Academy Course  

Thanks for being a part of the Community! 

-Taylor