@rajinsharwar Thank for your prompt reply.
Yes, I can use search parameter but it also search for the post content. I need to search for only the title with my query value. Chat GPT suggests me to use title parameter but it does not work.
When I try to get wp-json/wp/v2/posts?title=hello, it returns the posts without hello keyword in the title. As I inspected in the network, there is no specific error occurred.