Candidates who have got the invitation will receive an ITA(Invitation to Apply). They will have an option to either Accept it, Decline it, or Do not respond to it. If they accept it, the candidate would need to fill out a form similar to the ones in the EE profile. Instruction to fill out the form is mentioned in the ITA pdf file received in the message section of your profile.
More details of the draw can be found at this link –https://www.canada.ca/en/immigration-refugees-citizenship/services/immigrate-canada/express-entry/submit-profile/rounds-invitations.html