The best way is (their) way.
Truthfully there is no "best way" or "universally accepted way" for a couple to handle their finances. Some couples are fine with having a joint checking and savings account where one person is responsible for paying creditors and utilities.
This was very common back in the days where the man worked and the woman stayed home to care for their children. Oftentimes the wife handled all of the finances and gave the husband some spending money. There were also men who handled all the family's financial matters. Whomever was best with keeping track handled things.
Other couples have separate accounts and divide their financial responsibilities. One person may pay the mortgage while the other handles utilities, car insurance, groceries, and assorted items. In some instances they split everything like roommates.
Some people subscribe to having multiple accounts where the joint accounts are used to pay bills and the other accounts are used to spend as each individual desires.
This allows them to surprise one another with gifts and so forth as well as avoid arguments over how money is spent as long as what's in the joint account covers their expenses and savings goals.
Personalities and individual spending/savings habits will dictate the best path for a couple to embark on.
The worst thing one can do is attempt to (force) their mate into handling finances differently from what they want.
If both people don't buy into the plan it's doomed to fail.