need to devleop woocommerce add on plugin

To develop a plugin for woocomerce check out page the code ,database and webservice is ready we want a wordpress plugin so the functionality gets integrated with woo commerce checkout page its a OTP plugin ,so it should allow the customer to checkout only when success msg is received from our webservice call on validation of OTP from database.  WORK FLOW  customer fills the check out form .  enters mobile number .  clicks on SEND ME OTP button besides mobile number .  he gets OTP code on his number from our webservice .  customer enters OTP in Enter OTP field .  clicks Validate button .  service gives a sucess/failure msg .  if success --->>activate checkout button ---  Else --> invalid OTP number msg and checkout button is disabled .  re-enter mobile number ---validate ---repeat .  I provide client id to every plugin user so in settings tab he should be able to configure that so with every webservice call it is passed as a parameter.  There should be a option to configure twilio sms gateway in settings tab so that plugin user has the option to use there own sms account to trigger OTP sms. this plugin needs to be developed with word press standards so that any one can use it . [login to view URL]