The general scope of common magic spans up to roughly 7th level D&D spells with a handful of caveats
Well, damn. I don't know how obvious it would be to casual visitors, but your big governmental/management spells include Detect Thoughts (Wiz 2) or Zone of Truth (Clerical 2) [3.5e spell levels], and Sending (Clr 4, Wiz 5). The first two radically change judicial proceedings and anti-corruption investigations, possibly even employee management, or marital relations. The last has very limited capacity but is still useful. Cheaper but a bit more exotic is Animal Messenger (Brd 2, Drd 2, Rgr 1) which lets you use messenger pigeons without having to raise and cart pigeons around.

Alternately if a lot of people have one level of Wiz or Sor, they can have bird familiars -- messengers smart enough to fly back and forth between locations, or even people they can recognize. Like pigeons but a lot more convenient. Plus the aerial surveillance capabilities in warfare.

The real world had pigeon post -- medieval Europe seems to have been deficient in this, compared to the ancients, or to the Arabs of Crusades times -- but making it cheaper and more convenient is a big deal, as is familiars or Sending to 'radio' field forces -- real pigeons could only be used by field forces or agents[1] to send messages back to a base, you had to send a human to give orders to the field.

[1] One trick apparently was a "release on capture" pigeon; if the pigeon flew in, even without an attached message, you knew the agent had probably been in imminent danger of being captured or killed.