Write permissions sd card marshmallow 6.0 id3-tags

Ok, so I'm not got to act like I know what I'm talking about, but I've done a fair bit of googling and stuff like 'write permissions' have come up over and over again when searching id3 tag editors.

My question is, how do I edit my music titles? ie album name and song title. Some of my songs have unknown artist or album.

I have a LG G4 with marshmallow 6.0, my old G4 had lollipop and I could edit my music with an app. That phone got run over, my new G4 now has marshmallow. I bought it a few weeks ago.

The apps that claim to work don't, black music player had a built in editor and it looked promising, it let me edit my music but after exiting the app and going back in, it had changed back to the original title.(two hours of my life I can't get back.)

So is there anyway around this with a simple fix? Nothing too technical please like 'rooting' whatever that is....or I've read you can convert your external sd card to become an extension of your internal storage somehow...and I've heard bad things about that too, like lag and storage issues.

I just want to organise my music...something I enjoy dong.

Any ideas would be great.
Thanks,
Beck.