Call controller from an external api's request AND / OR strapi's admin dashboard

Hello, sorry for late reply,

You can use lifecycles for this to trigger your create service from Strapi’s admin.

module.exports = {
  lifecycles: {
    // Called before an entry is created
    beforeCreate(data) {
   //trigger your custom code here
    },
    // Called after an entry is created
    afterCreate(result) {
   },
  },
};