If you'd like to include a dial-in number and conference ID for your Teams meeting, do one of the following:
Schedule the Teams meeting from Outlook. Those meeting details are automatically included.
Schedule the meeting from Teams, but make sure PSTN conferencing is turned on for your account. (Talk to your IT admin if you're not sure.)
If a dial-in number is not available for a meeting, the feature may not have been configured by your IT admin, or the correct licenses may not have been purchased or applied.
You must send the meeting invite to at least one person for the dial-in info and Join link to appear.