If you would like to respond to the company after receiving your employment contract, here it is a simple template you can use to write an acknowledgement letter for an employment contract.
This letter is to inform you that I have successfully received the employment contract for the job position of [job title] at [company name]. I have gone through this contract, and everything seems to be in line with my interests. However, I will get back to you in case a query or a doubt ever arises.
I would like to thank you for being so prompt with the contract and paying heed to all my requirements.