I Have Attached Warning Letter Format
Name of the Company
The Managers of the Company has been making a researching and evaluation about the performance of your work during last few months and the conclusion was, the performance did not have the quality and the efficiency unlike past years/months.
The low performances has occurred during the months of January and June, in those months your performance and development were evaluated and the graphics show us that your work does not count with the quality enough to fulfill the necessary demands.(can write the actual reasons here)
If the low performance is not improved during a reasonable period of time, you will be fired immediately with no regrets.