I would strongly suggest that if your developer says that they will upload your app on their developer account that you refuse. You want full control of your final app and what happens with the financial aspect of your app.

In order to upload your app, you will now need to sign-up to the iOS Developer Program so that you can submit your new app to the App Store. Currently this costs $99 per year.

There are two options: signing up as an individual or as a company.

If you are signing up as a company and not an individual, you will have a few more hoops to jump through to get approved. This could include sending incorporation papers or other legal documents to Apple. Expect the total iOS registration process to take up to a few days.

The approval process times as an individual tends to be quicker.