How Can I Allow a Developer to Upload My App?

So new I may not know the correct terminology, thanks for your patience.

I hired a developer to create an app. He coded in React Native. He does not have a Mac so I am talking with another developer who has one and says he needs access to my account (individual account) to generate a signing certificate to be able to upload it.

I tried giving him access as a "developer" but he says he needs "account" assignment. I do not want to give that level of access. I borrowed a Mac from a friend and am wondering if there is a way that I can generate whatever certificate is needed, send it to him so he can upload app under developer access? If so, which certificate option do I need to get?

When I asked the original coder what language he used he gave this response..

react native just run command react build ios but he need have macbook

My next question is, can I do that from the Mac I just borrowed? And would that process be via X code?

Thank you for any advice.

says he needs access to my account (individual account) 

Whatever he/she says, true or not, NEVER give your user account access to someone else.

That's the one for sure thing I'd never do.

When you are working with a trusted developer, the normal procedure is to add them to your Development Team on App Store Connect (Users and Access).

You assign them an appropriate role (depending on what you want them to do), which might be (for example):
• Developer (for development)
• App Manager (for distribution)

The role allows the developer to do what they need to do, and no more.
For example, no access to your accounts!

With an untrusted developer, then things are much harder.
You either need to do things yourself, or find someone that you do trust, and get them to do it!

On Users and Access, you can see the exact "Permissions" that each role has (for the apps you have assigned to them), to help you decide which to use.

More information here:
https://developer.apple.com/support/roles/

Thank you @robnotyou

I tried assigning the role but they still couldn't generate a certificate. I then contacted Support and was told with my type of account (individual) I had to generate the certificate myself. Now I'm wondering how, like if I need to do that from a Mac, and how to send that certificate to the developer. I appreciate your response.

I looked back through the email chain with support and this is what I found

"Individuals enrolled in the Apple Developer Program can give additional users access to their content in App Store Connect, however, these users will only receive access to App Store Connect and are not considered part of the team in the Apple Developer Program. They will not receive access to other membership resources or benefits.

As the Account Holder, you may create these assets, and then export signing certificates and provisioning profiles for your developers."

So, I guess my next question is, do I have to do that from a Mac computer, and which of the signing certificates, and or provisioning profiles, do I need to generate and send the developer?

The developer said they could generate certificates if I could share my screen on "anydesk". Is that something that is safe?

How Can I Allow a Developer to Upload My App?
 
 
Q