OK, so I used to DM for AD&D (Advanced Dungeons & Dragons) between 1979 and 1982. Back then drew my dungeon maps by hand on graph paper. Sometimes I would photocopy a map from a different (usually commercial) source, then use Wite-Out to obliterate some part of the map, then I could draw in changes. I used some commercial dungeon adventure modules such as “In Search of the Unknown” and “The Village of Hommlet” but quickly found that the players were also purchasing and reading those modules, just so they would know what they would encounter and find in a particular dungeon. So, I then started changing things around. I would photocopy the pages of the module (for my own use!), and then write in changes, sometimes using Wite-Out to overwrite sections. Then I started making my own modules, writing out area descriptions by hand on a yellow legal pad, although eventually I started using a typewriter. (I didn’t purchase my first home computer until after I quit playing D&D.) After making changes to modules, it was always cool to describe what was in a room, only to have a player say, “That’s not what’s supposed to be in that room!” And then, of course, I could answer, “Aha! So you’ve been trying to cheat!”
So, now, when I picked up DMing again in 2015, I find using a computer makes everything a lot easier. I can take my hand-drawn maps and scan them and then edit them (or just plain clean them up) in Photoshop. I use Word to write descriptions, and use Excel to create various other play aids. I even use FileMaker Pro to keep databases of various things. It’s also easy to find other adventure modules online, then modify them so the players can’t search online for what adventure module we may be using! I change every place name or character name from other folks’ modules I use. I hope the authors of those other modules will forgive me. Believe me, the only reason I change everything is so the players can’t cheat and search on their smartphone while we are playing (I did catch one player doing that). Not to mention you can use your color printer to print floor tiles, paper figures found online, etc.
I also encourage players to keep their own notebooks, to record names of NPCs (non-player characters) they encounter, or places they visit, or artifacts found, etc. However, some players now keep notes on their smartphone instead of using paper and pencil. But of course, while they may only be keeping notes, I figure they’re also furiously searching online for what module we may be using!
So, in other words, using computers makes it easier to be a Dungeon Master, although it can also make it easier for players to “cheat”!
— The Dungeon Master