See active timers on your Lock Screen
When you use Timer+ on an iPhone running iOS 16.2+, your active timers should show on your Lock Screen as Live Activities.
The first time you see Timer+ on the Lock Screen, you'll get a prompt asking if you would like to keep it. If you do, tap Allow.
If you start a timer via Shortcuts, your Watch, or a URL, you won't see the timer on your Lock Screen until you open Timer+. Apple requires that third-party apps like Timer+ be in the foreground (app is open and visible to you) for them to send things to the Lock Screen.
If you accidentally tapped Don't Allow when you first saw Timer+ on the Lock Screen, or you're not seeing your timers on the Lock Screen anymore, open the Settings app and find Timer+ and tap it. There you'll see the switch for Live Activities; make sure it's on.