8gb SD card only shows 64mg after install?

I hope this is a simple answer. I just installed an audiophonics 8gb card and set everything up on the PI4 including the 9038 Dac. All is good except when I try to add to the card, it won’t let me because it says no more disk space and that total disk space is 64mg?

Research on this site revealed the following:

“The problem is also with larger cards. My 8 and 16 also had a problem. This is not about the card, but about the fact that after installation and launch volumio does not extend the partition for the remaining free space.”

So how to fix this? Please

Or just touch /boot/resize-volumio-datapart

Thank you for the replies. I got it fixed !

How and where do you enter that code? And it matters if I have no space left on the sd card? I also used a 64GB micro SD card. And I don’t even know how much space I have left or if it matters.