Pay components are not visible under dropdown via Take Action -> Change Job and compensation Information -> Compensation Information -> Pay Component Recurring and Pay Component Non-recurring.
1. All the fields with 2 choices as option in the dropdown should have a value assigned. For example fields like, Pay component Type, Target, Can Override, etc.
2. Please verify whether the pay components are country-specific by going to Manage Data -> Country -> Select any country's value and make sure there is no association with pay component wrapper object.
You can verify this by going to Configure Object Definitions -> Country -> scroll down till Associations. If there is an association with Pay component wrapper object, it means pay components are country-specific and county object (under Manage Data) should have assigned pay components so that the users belonging to those countries can be assigned filtered pay components.
For more details about that feature see EC Master Implementation Guide https://help.sap.com/viewer/b14dd15ca58f43e0856184a740a4b212/1805/en-US/f68ae232ab644d319b32311301593bae.html?q=Setting%20Up%20Country-Specific%20Picklists%20for%20Pay%20Components
chapter Setting Up Country-Specific Picklists for Pay Components or Event Reasons
And see Implementing and Configuring Employee Payments in Employee Central https://help.sap.com/viewer/0514f99ba10b466aa4d89b3eb3d8ff10/1805/en-US/57bed6ee46ec4f448a23c03813a18d11.html?q=Setting%20Up%20Country-Specific%20Picklists%20for%20Pay%20Components
chapter Setting Up Country-Specific PayComponents
Country specific pay components, Pay component not visible, employee central, SuccessFactors , KBA , LOD-SF-EC-CMP , Compensation Information & One-Time Bonus , Problem