Is there a way to make sure your windows laptop and iphone has zero malware/keylogger? I only use windows defender with my laptop.
For apple iphone i did use avast to do virus scan but it doesn't seem to do anything?
To make sure your system is clean, do a clean installation.
First, your Windows system must be licensed. Do not download it from various other sources, torrents, etc.
After that, install a good antivirus for yourself, it is imperative that it also has a license. But the built-in antivirus Windows 10 also, as practice shows, copes well enough with protection. Keep your system up to date, do not disable anything related to security. Do not download anything from unreliable sources, use sandboxes or virtual machines for all sorts of dubious software. To work with finances, in general, limit your activities to visiting dubious resources.
The same goes for your Apple iPhone. Check your phone through your computer, and also do a full iPhone reset, and after that do not forget to make clean backups and update your device on time.