Is it possible to inject and run malware on Windows 10 by knowing the victims IP address only?
Generally, no. Having someone's IP address is enough to try attacks but unless your system is vulnerable, it shouldn't be possible to execute code remotely. That being said, Windows may have vulnerabilities.
4Any software with a decent amount of complexity has vulnerabilities. Just maybe no known ones. Apr 27, 2018 at 16:27
This is like if you know someones street address ... can you eat pizza out of their fridge?
It is way too broad and depends on too many things. Are the people home? Do you know how to pick locks? Do they even lock their doors? Do they have a dog? Do they have a doggy door? Do you want to physically eat the pizza or would infesting the property w/ roaches, bedbugs, termites suffice to make the pizza in the fridge no longer useful.
No, it's not. An IP address is just how you know one machine from another - it's not a secret and not any sort of key to the machine. If it were possible, every machine would've been infected simply by attacking all 4 billion possible v4 IPs.
There is a lack of context here, but the general answer will be "no". Other answers will depend on what "remote" means in your case (i.e LAN or over internet). Then on the patch level of the remote host. Then it will depend on how much user interaction is allowed (i.e no user interaction, just like plug n pwn, or a bit of social engineering)...