Session replay is an add-on feature for paying customers only. You may try the feature for free for 14 days or 10,000 sessions (whichever comes first), after which you must contact Sales to continue use.
Session replay is for Web only. Native mobile (Android, iOS) session replay is not currently supported but is on our roadmap.
Yes! Navigate to Account > Manage > Session replay, then select the Privacy and Security tab. On this page, make sure Redact all text is selected.