How do I upgrade the video quality to 1080p for Livestream or video podcast?

Good luck with that!  
You need a very expensive account to get actual 1080p. Zoom has made it very clear they are not interested in supporting the podcaster market. They are a live meeting platform. 
I suggest you look at Ecamm if you are on Mac. 

Thanks. As it happens, I am on a PC (i7 processor with 6-core & 16GB or RAM) and the OS is Windows 11.  YouTube Studio and OBS do allow for streaming in 1080p.  I should point out that I've only one 24" monitor.  The only secondary monitor is my 10.4" tablet.  

I'm visually impaired and the idea of dealing with the chat stream is not my favorite thing. I'd rather keep it to a minimum.  Oh, I can see if there's activity but not be able to quickly read the chat. I'd have to get close. Video podcasting is no problem because I'm focused on the camera or the main video area.  

At least, I can use Zoom to record my interviews.  Then it is a simple matter to use my video editor to upgrade the video quality to 1080p.

In order to request 1080p on your account you need to be on a Business Account or higher. A single user on a Business Account is advertised at $199.90 US on the Zoom site. It also notes that a Business Account requires a minimum of 10 user accounts or more. So, the starting point would be approximately $2,000/yr for a Business Account with those 10 users.

Once you have this they will turn on 1080p. It's 720p till then, and still requires that it be requested.

This is a real shame since our church has been using Zoom since the pandemic began and will now be looking for another service despite how much we like and have come to depend on Zoom weekly.  We are a non-profit with no reasonable way to move to a $200/mo account.  Wouldn't a $10-$20/mo increase cover three hours of 1080p once a week?  SMH