The inquiry chaired by the former Moderator of the Church of Scotland, the Very Reverend Dr Andrew McLellan, CBE, said the help of victims would allow him to build up a "full and clear picture" of current and past safeguards and procedures.
He added: "To do this, we have to listen to survivors of abuse and harm and we urge people to get in touch with us in confidence.
"Our task is primarily to help to protect children and vulnerable adults and we want to help the Catholic Church ensure its policies and practices with regard to abuse are following best practice.
"The only credible policy for a church is no abuse, no cover-up."
Commissioners are meeting with interested parties and listening to expert opinion on best practice in safeguarding children and vulnerable people.
Although it is not within the scope of the Commission to investigate or adjudicate allegations, the Commission will take account of the experiences of survivors of harm and abuse within the Church.
A secure area of www.mclellancommission.co.uk has been set up for victims to contribute, but anonymous responses will not be read or dealt with.