First and foremost, an Attestation Officer is an individual who is empowered by public authority to administer an Oath of Identity - and who knows how to do it properly. In this age of rampant inauthenticity, the world needs measurably reliable identities so that people can know with measurable certainty that other individuals are who they say they are.
"Doing it properly" means really following through on the administration of an oath rather than simply sealing a document saying that it was done. For that reason, an additional qualification such as the Signing Agent certification from a recognized notary association for American notaries or equivalent certification in other jurisdictions is also required. "Doing it properly" also means using a webcam to record the event, and digitally signing the video and associated files. If you know how to use a laptop, its not at all difficult.
The principles are the same as with any administration of an oath, with the addition of a digital certificate to the customary paper affidavit and certificate or jurat.