HI Zeeshan,
all entities from Attract are available in CDS, since Attract is a Powerapps application (sort of...). For the moment, unfortunately, you cannot customize Attract, Offer Management or Onboard. (they have their entities and data available in CDS). Probably this will change in October 2019...but there is no clear guidance for this.
If you need to capture additional data during the recruitment process, the recommended way is Microsoft Forms Pro.
regards,
nicu
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