How can I make reminders appear on my lock screen?

The Reminders widget only shows upcoming reminders. That is, those with a date/time set for them, and that date/time is still in the future. If you set reminders without a date/time, they will not show in the widget.

HOW TO SET THE REMINDER:

set it to the current day, and 5-6 minutes ahead of the time it is now

then make it never repeat ( as seen in the picture )

TO MAKE IT STAY ON THE LOCKSCREEN :

lock your phone and let the reminder ring out, don't mark the reminder as completed until you want it off your screen.

if you don't mark it as completed, it won't come off of your screen

make sure you have the notifications on as in picture 2