Good day

I've being this forum for not quite long , coming here at first didn't understand anything about bitcoin technical part first time I encountered a discussion in this thread it seems interesting, got me feeling dizzy was like seeing some words haven't seen before.
But I was still moved to learn about it then I actually started learning about  technical part of bitcoin and I can see some improvement. But I'm still on the wallet part during my research found out malware can cause damages to our wallet (software wallet because is connected to intern) . And mostly use by hackers but still don't get it clear. I actually vibe learning from different sources and this forum one of them.
My questions are:
•What damages can a malware cause to your wallet?
•What are the signs that your wallet being attacked by malwares?
•How can it be prevented?
Any one opinion is appreciated, thank you.