To move a rejected Applicant back into your Job's Hiring Process, start by clicking into your Job's Rejected Stage and clicking the three-dot button next to the the candidate you want to move.
Click "Move to Stage".
Select the Stage you wish to move them to.
Note: Keep in mind that they will receive any messages linked to a candidate's arrival in that stage. Therefore, before selecting where to move your applicant, make sure the messaging settings are adjusted for how you'd like the candidate to receive them.
Once moved, the applicant will appear in whatever stage you selected!