What I do to make certain about the payment posting is that on the BoA website, I signed up to have it paid directly from my bank via ACH. If you authorize the payment by (I think) 7 pm, it will post to your account that night.
Having the BoA app, many times as soon as I see it closed, I pay it off. So many times, it is paid a few days before I receive the bill in the mail.
At first, I thought you meant that payments get made automatically. Then it seemed that you set up a mechanism but need to trigger it each month.
All my credit cards (and utilities) allow me to set up automatic payments. The bank (or utility) takes the money from the designated account on the due date, without action by me. In the case of credit cards, I can designate that the payment should be the entire balance due. (There are other options, but I always choose entire balance.)
Long ago, when I first set up one of these automatic payments, I was assured that I could alter the payment if there was a charge that I disputed or if I just didn't want to pay the full amount. I have never tested this alleged capability.
Iowa City even offered a $1 credit each month on its water bill if the customer paid this way, because it simplified things so much for the city. (Contrast this with the state of Minnesota, which charges a fee to pay by electronic funds transfer on its web site, thus pushing me to pay by check, which requires a state employee or contractor to handle a piece of paper. Fools!)
In short, this system has worked for me, and I believe it beats writing a check or remembering to visit a web site to trigger a payment. My payments are all made as late as possible, so I get the float on the money (not that that has been worth anything since 2008).