Your podcast will likely already be on Google Podcasts as there is no submission process. Google scrapes the internet for RSS feeds, and then adds it to their platform.
If your podcast isn't available through Google Podcasts yet, it's likely because it's brand new. After a week or so, Google should pick it up.
If you want to find what your Google Podcasts URL is, you can use the tool linked below:
If you see any unusual errors you're unable to fix yourself, please create a support ticket and we will do our best to help.