How to hard format sd card on macOS?
This will erase all data that currently exists on the SD card:


Remove your SD card.
Open Disk Utility.
In the menu bar, click [View] > [Show All Devices].
Insert your SD card, ensuring the write-lock switch is in the unlocked position (towards the side of the card which has the gold contacts). You should see your SD card appear in the sidebar in Disk Utility as something like "Apple SDXC Reader Media". Click this item.
Click [Erase] in the top bar.
Enter a name of your choosing.
For the format, choose "MS-DOS (FAT)".
For the scheme, choose "Master Boot Record".
Click [Security Options...], move the slider to "Fastest", then click "OK".
Click [Erase].