Before you can schedule a visit, you need to be on the incarcerated person's approved visitor list.
The incarcerated person starts this, not you. They request CDCR Form 106 (the Visitor Questionnaire), sign it, and mail it to you. You can't download a blank one and start on your own.
List every criminal conviction and every arrest — even ones that never led to charges. CDCR runs a background check and can deny approval over anything undisclosed, not just anything that happened.
The completed form goes to the Visiting Sergeant at the facility, addressed to "Visiting" — this is usually a different address than the one used for regular mail to the incarcerated person. Use the facility staff/institution mailing address when CDCR publishes one; if the facility page does not clearly separate staff mail from inmate mail, call Visiting before mailing Form 106.
You'll get a letter with the reason. You can appeal: write to the Warden first (response required within 15 working days), then escalate to the CDCR Division of Adult Institutions if needed (20 working days).
CDCR sometimes allows a visit before formal approval for visitors traveling 250+ miles unexpectedly, at the Visiting Sergeant's discretion. Don't count on this — apply in advance whenever you can.