Working in a manufacturing company since 10 months

if you do not have appointment letter, you do not have rights. As per natural justice one month notice be given by either parties.

But I have salary Slip, salary Bank statement etc. And Sir GM sent me Notice for "performance improvement within a month otherwise termination"" on whatsapp. is whatsapp msg will consider as a notice? They Have right to terminate me after one month of this msg?

thanks.

In your case there is no proper emplyment contract. Salary paid and PF deduction is a proof of your employment and in your case there is a warning  on your performance and is a termination notice. Since there is no contract and normally no notice will be given.

It makes no difference that there is no appointment letter. There is a completed contract for employment. The employer is bound to follow the due process in termining an employee who is in regular employment.