Beatmap offset mod = This is an unranked mod, and when player activates the mod and then plays a beatmap, Osu! will assume that the player is always clicking on the hit circles in time to the music and will adjust the offset for the beatmap based on the results it receives from the player.
Universal offset mod = This is an unranked mod which works similar to the previous example, but when enabled will alter the universal audio offset for Osu! with the results it receives from all games played with the mod activated.
Universal offset mod = This is an unranked mod which works similar to the previous example, but when enabled will alter the universal audio offset for Osu! with the results it receives from all games played with the mod activated.