I'm downloading some mods to my single player game and sometimes some mods have the version 1.12.2 (that is the version I play), the version 1.14 or 1.15 and, between this, the version Forge+2. What means this Forge+2? Can I use it in my 1.12.2 game?
He means on the Curseforge website, I want to add mods to my minecraft game but they are all either 1.12.2 or forge + 2 and I'm hoping I can add this mod with the forge version up to 2 games above my current game level. For example I want to add Building Gadgets to Skyexchange (I am really lazy when it comes to building) and sky exchange runs on 1.10.2 and there isn't a version for it. Is it possible to add the Forge+2 mods to my 1.10.2 game? since it's +2 to the game I'm playing? Asking for myself not for a friend.
The forge + 2 thing is due to CurseForge displaying the version numbers in a really bad and annoying way. Forge itself is treated as a version number instead of as a mod loader or project type. So a mod for forge which supports 1.12.2 will be forge + 1. The Java version is treated similarly, so if they say java 8 (the default) then it is forge + 2. You may have to click on the file itself to see the real version.
For the average player it doesn't actually mean anything. Minecraft Java Edition uses Java as the name implies. Java 8 means version 8 of Java, this is the default version used by the official launcher.