@Goyal Hello, 

Tapo camera could be controlled remotely after being set up and does not require a phone to connect to Wi-Fi.

If camera works fine when phone connected to home wifi, but  becomes detached/ offline  when phone is using outside wifi or mobile data, you could try some suggestions  here: 

• Turn off or lower Modem/ router Firewall settings
• Check if there is any Advanced settings on router like access control/ parental control settings may affect the camera
• Change router's DNS to 8.8.8.8/ 8.8.4.4
• Reboot camera 
• Make sure camera is connected to router directly, not through other AP or Range extenders

If the same problem, may I know the model of your router and your network topology? Please help collect the log of camera and share with us ,thanks~ 

How to get the logs:
Step 1: Insert an SD card into the camera.

Step 2: On the APP, please go to Camera Settings -> Advanced Settings -> enable Diagnose. The log file will be stored on the SD card.
Step 3: Let the camera run for some time, wait for the recurrence of the problem.
Step 4: Please plug the SD card into the computer's SD card slot or an SD card adapter. Please send the log on the SD card to us. The name of the file is ‘Diagnose Log’.