In Salesforce, a child object with multiple parent objects is not available for selection as the Target Object in a 'Create a Record' quick action. This includes situations where standard objects behave like master-detail relationships, such as Account and Opportunity. In these situations, Salesforce does not allow you to create actions for the related child object when the child object has multiple relationships of different types.
Example:
This article answers the question: why can you not choose a child object with multiple relationships as the Target Object in a Salesforce 'Create a Record' quick action, and how do you work around it? This is Working as Designed behavior.
For Master-Detail relationships, a detail object record requires a master record when a child record is created. In a Lookup relationship, a detail object record can be created with or without a master record.
To create an action with object C as the target object on object B, use one of the following options. Before you change the relationships, review the Considerations for Object Relationships article listed in Additional Resources.
The workaround in the article "Cannot choose a specific custom object as the target for 'Create a Record' Global Action" is also applicable, but it is not advisable. It creates the action for the detail object before the master-detail relationship field is established.
001927677

We use three kinds of cookies on our websites: required, functional, and advertising. You can choose whether functional and advertising cookies apply. Click on the different cookie categories to find out more about each category and to change the default settings.
Privacy Statement
Required cookies are necessary for basic website functionality. Some examples include: session cookies needed to transmit the website, authentication cookies, and security cookies.
Functional cookies enhance functions, performance, and services on the website. Some examples include: cookies used to analyze site traffic, cookies used for market research, and cookies used to display advertising that is not directed to a particular individual.
Advertising cookies track activity across websites in order to understand a viewer’s interests, and direct them specific marketing. Some examples include: cookies used for remarketing, or interest-based advertising.