I asked her how she thought that would work and she said she didn’t know.
Fun fact, this is actually a real thing you can do, and the real ones aren't scams. (unless you consider paying a fee in exchange for quickly building solid credit history without spending money on goods a scam)
They're called Credit Builder Loans.
Essentially, you're not technically "putting money in an account", you're being given a loan at a future date, after you've made your payments. (basically just a reversed loan schedule) If you miss a payment due date, it hurts your credit just like missing a regular loan payment for money they already gave you.
Some charge interest (basically any given by for-profit companies/banks), some don't (mostly just the occasional credit union). They do exactly what the credit system is supposed to indicate, which is show that you can make payments consistently and on-time, regardless of if you got the money upfront or after.
Personally, I almost always would say secured credit cards and credit-building "debit" cards are a better option. (e.g. the Chime's and Step's of the world where your card limit is always your current balance and never more, except for overdrafts) If you look at a big credit builder loan provider like Self, you can see their plans result in you paying pretty large fees overall just to boost your credit score, like paying $600 in and getting $511 back on their cheapest plan. Ideally, you'd have a credit union that wouldn't charge a fee, but might just offer a low or no interest rate compared to investing it in a CD in exchange for them having to effectively hold that money for you instead of being able to offer it out for loans. (and even then, the term is fixed, so they can still loan it out as long as they know they'll get it paid back by the time your term ends)