Config is a customization that you store for each integration of all your end-customers. These customizations can then be used in the workflows for various use-cases.
Learn more about Config and its types here.
Consider an example where you want to sync all the contacts of a particular list from Salesforce and your users provide you the list from which the contacts should be synced. Provided below is an example of how a select config dataslot appears to users. Example of User Config Let’s add a dataslot of Contact Lists in Salesforce.
Learn more about Select Field Type here.
1

Add Dataslot in Config Portal

Click on the Config Portal in Salesforce and click on Add Field button.
2

Provide details

Provide a name to the dataslot and select Type as List Contact List Values. Click on Add Field.
Click on Edit for the dataslot and mark it as Required so that the workflow will not execute if this is not selected by the users.
Select Config Setup
3

Save

Click on Save Field and the dataslot is now added for your users to select a list in config.
To use this dataslot in the Sync workflow, you would need to change the action in Node 2 to Get Contacts Of A particular List and provide this dataslot in Enter List ID field.
You can get this Config of your users after they perform selection by using the Config API or SDK Method.
Navigate here to learn how you can manage Configs for your end users.