Hello. You did not enter the protocols to which this question refers, which makes it difficult to come up with an exact answer. However I will try to help you in the best possible way.
To create reminders about the use of the mask, you must spread posters, or even post-its in easy to see places, where all the people who will execute the protocols will be able to see.
These posters should have, in a striking way, information about the obligation of the mask and the dangers that can be presented if it was not used.
