There isn't going to be a physical mark until
Revelation 16:2And the first went, and poured out his vial upon the earth; and there fell a noisome and grievous sore upon the men which had the mark of the beast, and upon them which worshipped his image.
The mark of the beast becomes the only valid means of buying selling in chapter 13, which is in the middle of the seven years. Revelation 16:2 when the 1st bowl is poured out, it is just referring to those who will have already received the mark. The words "the men which had the mark" would infer that they already had it and which is why the painful ugly sores break out on them.
I would also add that, the mark of the beast which will be used to credit and debit ones bank account, could not just pop up over night, but that technology had to evolve. The system for the mark for digitally crediting and debiting (buying and selling) has been here for some time. People use it everyday when the go to the grocery store and make payment by swiping their bank cards using the Point of Sale system and the Verifone device. The mark will eventually replace this and all other digital payment methods and as previously mentioned, this technology is already being used in Sweden since 2015. Soon, instead of people swiping or tapping bank cards, we will see people begin to pay with the scan of their hand, just as those in Sweden are already doing.