I am working in one company I already three years...

If your inquiry is related to ending the contract after three years of service
If a worker under a definite term contract abandons his employment at his own initiative before the expiry of his contract period, he shall not be entitled to severance pay unless his continuous period of service exceeds five years.
On the other hand, a worker under an indefinite term contract abandons his work at his own
initiative after a continuous service of not less than one year and not more than three years, he shall be entitled to one-third of the severance pay provided for in the preceding article. Such a worker shall be entitled to two thirds of the said severance pay if his continuous service exceeds three years up to five years, and to the full
severance pay if it exceeds five years.
Labor Law Articles stipulate on,
Article 137
Where a worker under an indefinite term contract abandons his work at his own initiative after a continuous service of not less than one year and not more than three years, he shall be entitled to one-third of the severance pay provided for in the preceding article. Such a worker shall be entitled to two thirds of the said severance pay if his continuous service exceeds three years up to five years, and to the full severance pay if it exceeds five years.
Article 138
Where a worker under a definite term contract abandons his employment at his own initiative before the expiry of his contract period, he shall not be entitled to severance pay unless his continuous period of service exceeds five years.
Article 139
A worker shall forfeit entitlement to his entire severance pay in any of the following two cases:
1. If he is dismissed from service for any of the reasons specified in Article 120
hereof or if he abandons his employment in order to avoid being dismissed in accordance with that Article.
2. If he abandons his employment of his own accord, otherwise than in either of the two cases specified in Article 121 hereof, without notice (in the case of indefinite term contracts) or before completing five years of continuous service (in case of definite term contracts).