Can the format of mobile phone memory card still be used?

Yes, this happened to my mobile phone. I need to format it, but there is nothing left after formatting, so you should keep a copy of the important things after formatting.

It can be used after formatting, but the information/installation things that used to exist on it are gone.

Does your mobile phone come standard with sd card? If so, you can also search the backup of your mobile phone card first. After formatting, copy it and it will be as good as new.