​@omersaruhan yes its possible.you can activate comment reply trigger and then set your flow.

If you need any help for this, lets contact me.thanks.

Hello ​@omersaruhan ,
Yes, it’s absolutely possible to do that. In your first flow, where you collect the user's phone number, make sure the "WhatsApp" option is selected, just like in the screenshot below:
 

After collecting the WhatsApp number, direct the user to the flow that contains the message you want to send.
Important: since this message is intended for a user who hasn't interacted with you on WhatsApp yet, you first need to create a message template. This template must be approved by Meta, and only after approval will you be able to select it in your flow.