Some studios sell gift cards, prepaid packages of visits, and memberships you pay for monthly or yearly.
Each of these belongs to the studio that sold it. A gift card bought at one studio cannot be spent at another, a package of six blowouts is six blowouts with that professional, and a membership is a plan with them.
Expiry, transferability and what happens if you want to stop are all the selling studio's terms. Ask them before you buy if any of it matters to you — those are exactly the questions professionals expect and are happy to answer.