Hi VadimK,
As I understand, you want to host your website on Office 365, and your domain registrar is GoDaddy. Please correct me on time if I misunderstand the issue.
If so, you can change your public-facing website to use a custom domain name instead of using the domain name that you chose when you signed up for Microsoft Office 365 for professionals and small business, you may use the Change Address after you’ve added and verified the domain in Office 365. This you don’t need to get the IP address of the website, Microsoft will change this for you.
You may refer to the references below:
Use a custom domain name for your SharePoint Online public-facing website address
If you don’t want to use Office 365 to host your website, when you add your domain to Microsoft Office 365 for professionals and small businesses, you can keep your current public-facing website that uses your domain with an outside website hosting provider instead of hosting your website with Office 365. You need to create a DNS record in Office 365 called an A record that points to the IP address for your website. For the IP address of the website, you should contact your current hosting provider.
For detailed information, please refer to the article below:
Update DNS records to keep your website with your current hosting provider
Thanks,
Eric Sun