Questions, bug reports or ideas: vovchak001@gmail.com. Please say which iPhone and which iOS version you use.
Use the Share button in Safari, Photos, Files or any other app and choose Snip. Pick a snip, add a note or tags, and tap Save.
Yes. Saving never waits for the network, and saved pages are archived on your device.
Open the snip's menu, choose Edit and turn on the lock. Locked snips need Face ID or your passcode and never appear in search or the share sheet.
Check that iCloud is on for Snip in Settings → your name → iCloud, and look at the sync card in Snip's Settings. Very large files stay on the device that saved them.
Open the snip's menu and choose Share Snip. Send it with AirDrop or Messages and open it in Snip on the other device.