I’ve been using Maps.me for orientation. It does allow me to add things and sends them to OSM. But it has a fixed list of “Category” which does not include “other”.
This is disconcerting, because many of the things I’ve wanted to add are NOT on the list.
Does this list come from OSM, or is it a design error in the app?
That is a design decision made by the maps.me developers. You have to contact them for improvements in that area.
Or you could use OSM online editor…
Can’t do that when I am off-line out on the road. But I guess I can resolve my own notes later on. So far, other people have been fixing the errors the app imposes on me. I’ve sent a few messages to the app folks. The only response was telling me where to get the source so I could do it myself. I retired from more than thirty years of software engineering. Now, I’d rather travel than maintain code. 
For what it’s worth, I have finally gotten the hang of using Go Maps! On the iPad for editing in the field. Far superior to maps.me for editing, though sometimes the need to download tiles in advance is inconvenient.