In order to complete this exploration achievement, you have to find a beggar NPC on every map (optional level 1-5 zones are excluded, Cyrodiil and Coldharbour as well). NPC can be male or female, wearing rags, with the follower icon above their head. There are multiple spawn locations on every map and all are beside roads with no hostiles near that point, but only one NPC can exist in one zone at any given time. Also, NPC despawns a few minutes after any interaction (logging out definitely does that) and that makes it even harder to find a beggar in peak hours.
The Elder Scrolls Online Achievements are incentives in the game that offer rewards to a player for every accomplished specific task.
TESO achievements are divided in numerous groups representing different styles of play: PvP, PvE, defending the keeps, crafting, quests, etc. The list of achievements in TESO will be long with pretty good chances that over time it will be expanded.