Hey @Sahil Mehta ,
It is possible to invite a guest user who doent have email configured.
Ones need to log in into Azure AD and resend the invitation to the user. After resending the invitation, the Azure AD login would get a URL which he needs to provide to the guest user for accepting the invitation.
Below blog : https://datasharkx.wordpress.com/2021/05/13/inviting-guest-user-accounts-with-no-mail-enabled-to-an-azure-active-directory/
should help for much better understanding