We have migrated contact records in marketing cloud data extension and it is constantly updated. We need to have those customer details in all contacts with memberId as contact key. Can we automate to create these contacts as it is added in the data extension?
If you are using the FTP, then you can use the same file in FTP to import Subscribers [Email - Contacts] via Import File activity, to the "All Subscribers" as below.
Once they are added to all Subscribers, they automatically gets added to Contacts, specifically for Email channel.
As Best practice and to double confirm on mapping, use map manually option as below,
Finally as per your requirement you can put this Import definition in a Automation either as File drop or as a Scheduled as per your requirement! Hope this help!