What you're asking is 2 unrelated questions so I'm not sure what you're actually trying to do.
Deleting an Azure tenant would apply if you're using Entra or B2C. In that case you have to delete the organization (the tenant). To delete the organization you must be the global admin. If you are not currently the global admin then you'd need to become one first. The only way to become a global admin is to either be the user who created the organization or be granted that permission by someone who is already a global admin. This is all for obvious security reasons. If you have neither then you'd need to get in contact with Azure Support directly and they'd have to work through the process of confirming who you are and whether you have legal rights to the organization. That is going to take some time and is beyond what can be done in these support forums.
Deleting an Outlook account has nothing to do with Azure. Anybody can have an Outlook email account and it is not directly tied to anything in Azure. To permanently close your Outlook email account you have to close your MS account. The steps are discussed here. Be warned that this would break anything connected to your MS account including Windows, XBox, these forums, etc. If you no longer want to use Outlook as your email provider but want to keep your MS account then just stop having emails sent to the Outlook account, set up forwarding to the email you want to use if desired and then ignore it. It doesn't cost anything to have an OUtlook account.