Is it possible to submit for the first time to App Store through

My first post here!

I think the question in the title is pretty explanatory but let me elaborate:
I have an app that I want to submit to the App Store. I think the online build/deploy service through is pretty useful so I decided to try it out.
I have got a build and deployed it on the production channel.
But submitting to App Store is a completely separate topic, right?
So is it possible at all to develop without a Mac?

I have been struggling for many hours to submit through XCode but it keeps getting rejected when uploading to App Store with an ITMS-90034 error (that I supposedly didn’t sign the archive with an Apple Submission certificat) but I’ll open a separate thread about that if needed.