Hello there!
Your question asks what the maximum amount of money that a person can charge on a credit card is called.
Answer: Credit limit
The reason why "Credit limit" is the correct answer is because this is the maximum amount that a user can use on their credit card.
Banks put credit limits on people's credit cards so that the person who has the card doesn't keep using on a bad spending habit and would have trouble paying the credit card bills. Credit limits allow people to know that they can only use a certain amount of money that has been provided by the bank for them.
For example, some credit cards have a $500 credit limit, some have a $1000 credit limit, and there are a few credit cards out there that have no spending limits. American Express (AMEX) is known to give credit cards that have no limitations on the credit, which means that the person can use the credit card and spend how much they want on it without worrying about exceeding the "spending limit."
If banks were not to put credit limits on their cards, people would just keep swiping, swiping, and swiping with the credit card and would have trouble paying off the credit card debt later on. Banks would suffer if they gave everyone a "no limit" credit card, due to the fact that they would be losing a lot of money because people can't pay back the debt. The people would probably only pay the minimum fee, but not pay the whole thing anytime soon.
I hope this helps!
Best regards, MasterInvestor