Even after long tapping a particular message in messaging app,the reply option is not showing in drop down menu. Only Copy and More options are coming. Currently running through iOS 14.1. How to solve it?

Hi soumik114,

Thank you for using the Apple Support Communities! We understand you are not seeing a Reply option when long-pressing on a message within a conversation thread. We'd like to help.

What you are describing is expected behavior if you are long-pressing on a regular SMS message. The Reply option only appears when long-pressing on an iMessage. Regular SMS message threads can be identified by the green bubbles, and iMessage threads can be identified by the blue bubbles in the conversation thread.

Reply to specific messages on your iPhone, iPad, and iPod touch - Apple Support

Best regards.