You can do this once you have successfully added a TXT record to your domain records, verified ownership of your domain on google search console, and have your generated sitemap URL ready to go.
Kindly click here to read how to verify domain ownership if you have not previously done so. If you have verified your domain, follow these steps:
Step #1: Log into your google search console dashboard here.
Step #2: On your dashboard, look to your left, towards the bottom of the page, you would see a ‘sitemap’, click on it
Step #3: You would now see a text that says ‘add a new sitemap’, paste in the URL of your generated sitemap
Step #4: Click on submit.
That’s all. Got questions or feedbacks? comment below.
If successful, you will get a message saying sitemap successfully submitted.
If you have a WordPress website and you use Yoast plugin for SEO, follow the instructions here to see your sitemap URL.