Telegram Registration and Login Guide

Conclusion

To successfully register and log in to Telegram, it is essential to use the official client. It is also highly recommended to enable two-step verification for enhanced account security.

First-time Registration: You must use the official mobile app to register, in order to receive the verification code via SMS.
Desktop Client: If you attempt to register using the desktop client, it will prompt you to register via the mobile app.
Third-party Clients: When using third-party clients, even if it prompts to send a verification code, you will not receive the SMS. This is because Telegram has officially disabled registration and verification code functionalities for such clients.

Existing Account: When logging in again, the verification code will be sent directly to your already logged-in device.
Without Two-step Verification: Log in using the combination of your 'mobile number + verification code'.
With Two-step Verification: You will need to enter the combination of your 'mobile number + verification code + two-step verification password' to log in.

It is strongly recommended to enable Telegram's Two-Factor Authentication (2FA) to protect your account security and privacy.
Regularly review and adjust your privacy settings to prevent information leakage and avoid being unnecessarily added to groups.