Dear Vandana, you are absolutely right. An appointment letter is also an agreement between the employer and employee. If the same movement is not mentioned in the appointment letter, it can be designed separately.
Confidentiality & Non-disclosure Agreement
Confidentiality & Non-disclosure is an agreement between two parties that outlines confidential material, knowledge, and ideas that may not be patented and could be a trade secret. Under this agreement, you cannot disclose any information of your employer's business intentionally (for your profit) or unintentionally (such as client lists, distributors, or suppliers' names and the prices offered by them, which could vary and be the basis on which decisions are made) that could cause a loss to the business. Even after you leave the organization, you are bound by this agreement until the specified period mentioned in the agreement.
I hope this information helps you.
Regards, Vandana Malik