Level 2, all good-aligned characters should gain it upon advancing that far.

The helpfile:
Syntax: beseech <non-player character>

Virtuous characters may persuade others of similar morals to provide some
assistance if they are in dire need. Healers and paladins are the most
capable and most renowned for having a generous spirit, but it may be
possible to obtain aid from others.

Persuasive characters will find obtaining this type of aid the easiest,
particularly when their need is slight or they have developed a reputation
for asking quite often.

See also: HEAL, MORALITY, REQUEST

valguarnera@carrionfields.com

The two I tried so far told me they couldn't help me, which seemed odd as I think they were both paladins. For instance one is Tristan the Paladin in Barovia? Figured some just got overlooked possibly? Should I report those through typo or something?

It's not guaranteed to work, especially if you don't seem to need much help, or if you've asked around for help a lot recently. Experiment.

Back in my day, it's how we rolled!

valguarnera@carrionfields.com

I was trying out this skill just to see what it could do, and I kept getting a message about not getting anything without offering something in return. Not sure what that is about, but it suggests to me that perhaps the syntax isn't complete, like beseach <NPC> <item or gold> is the way it should go, but maybe I just wasn't trying npc's with the command enabled or something.

Tac

You need to put some practices into it.

valguarnera@carrionfields.com

Persuasive characters will find obtaining this type of aid the easiest,
particularly when their need is slight or they have developed a reputation for asking quite often.

It seems like having a reputation as a leach would be a turn off. Was that, by chance, supposed to be "a reputation for asking infrequently"? Or are you trying to say something more like "a talent for mendication"?

The way I read that is:

It's harder to beseech if you're doing it too often, but a high charisma alleviates that penalty.