You need to have Static IP (Fixed IP). or any other service like DDNS

After you got any Fixred IP or DDNS, check "http://yourip:9000" from out side your Home network, It need to say "TallyPrime Server is Running", 9000 is Tally Default http port, you can change that port number any other port as you wanted for Security reasons.

After you got reply from Tally, contact us to use this Portal, or WhatsApp to : 8500012345