Build a Wordpress Plugin to submit a form through API

Hello friends, i am a core php developer and have made a platform for Health checkup campaign's registration. All you need to create a plugin for wordpress by which a visitor can post a form to our website. the url structure will be like this way: http://www,[login to view URL] http://www,[login to view URL] This url will remain same for all wordpress [login to view URL] you can make plugin to write into htaccess or any method you want. i just want this to communicate with my server via the API i give you. it's a simple POST API also i can change the server side according to your ease. since i am a core php developer i have good idea so i can guide you through process too. thanks