Lots of things change after you file for divorce, and it represents just the beginning of many changes.
The best plan is built around your own abilities to provide for yourself. If you are working, set money aside. Do it in a way that does not disrupt your normal financial operation, but you want to have a cushion. Your husband could stop providing you with any funds once you file, and so you want to be ready for at least two months of expenses. Plus, you want to have money to pay your attorney. Best to plan ahead.
If you have not ever had credit cards in your name, it is time to open one. The credit limit does not have to be huge, but you want to be able to survive for several months. This will also help you in the future as you get loans to replace a car, buy a home or undertake other needs.
If you and your husband have funds in savings or that are otherwise liquid, make a plan to withdraw up to half of those amounts at the time of the divorce filing. Once a divorce case is filed, an injunction goes into effect which stops the filing party from taking certain actions: transferring, concealing or disposing of assets; harassing or intimidating the other party; using the other party’s information to open up new accounts; cancel utilities or other services; or make changes to insurance policies. That means you cannot withdraw from the bank account or open up new accounts in your husband’s name. So, any withdrawal from the bank needs to come before your divorce case is filed. You should put those funds (along with your paycheck, if you receive one) in a new, private account.