First is important to note that, according to ISO 27001, the security requirements to be included in contracts with suppliers must be based on the results of risk assessment and legal requirements your organization must fulfill.
Considering that, some common requirements are:
Right to audit: clause ensuring the organization has the right to audit and test the security controls periodically, or upon significant changes to the relationship.
Notification about security breaches: clause requiring the provider to inform the organization in a timely manner regarding any security breaches that may impact the organization’s business.
Adherence to security practices: clause requiring the provider to adhere to the organization’s security practices, and to communicate any situations where this adherence is not achievable, helping to prevent security gaps or conflicts that could impair security performance.
This article will provide you further explanation about security clauses for contracts: