A managed package is a type of app that can be installed from the AppExchange. Managed packages are typically created by ISV partners or developers who want to distribute and sell applications that are upgradeable and have intellectual property protection. Before installing a managed package, an administrator should consider the following:

A) Custom objects and custom fields used by the app count against the org’s limits.

Managed packages may include custom objects and custom fields that are used by the app. These custom objects and custom fields count against the org’s limits and may affect the performance or functionality of the org. Administrators should review the components and requirements of the app before installing it and make sure they have enough space and resources for the app. References: https://help.salesforce.com/s/articleView?id=sf.packaging_limits.htm &type=5

C) Apps may require certain Salesforce editions or features to be enabled.

Managed packages may require certain Salesforce editions or features to be enabled in order to work properly. For example, some apps may require Lightning Experience, API access, custom permissions, or specific user licenses. Administrators should check the app’s description and documentation before installing it and make sure they meet the prerequisites for the app. References: https://help.salesforce.com/s/articleView?id=sf.packaging_install.htm &type=5

D) Apps may require external, third-party web services to function properly.

Managed packages may require external, third-party web services to function properly. For example, some apps may integrate with other platforms or systems such as Google Maps, PayPal, or Twilio. Administrators should check the app’s description and documentation before installing it and make sure they understand the implications and costs of using external web services. References: https://help.salesforce.com/s/articleView?id=sf.packaging_install.htm &type=5