My Google-Fu has failed due to the wide variety of contradictory information on this subject. Simply put, in Windows 10 can you manually type a string to get a Unicode character? The answers have varied between yes, no, yes but you do it completely differently in Google applications, yes but only in Notepad, no but you can embed it in HTML, not on a laptop, etc. etc.; not to mention four or five differing sets of instructions on what keys you’re supposed to press, hold, let go, etc. including whether + means “at the same time” or the actual + key on the numeric keypad.
Note that I’m not talking about the simple upper ASCII set accessed by the Alt key plus keypad numbers-I’ve got that. I mean any Unicode character that my screen will display.
You can get at some Unicode characters. Try Alt+1 for a smiley face. But this doesn’t work generally.
It seems that the only reliable way to get all characters is to set the EnableHexNumpad regkey. Then, you can hold Alt, then type the numpad +, and then the hex string of the Unicode code point. I haven’t tried this myself.
I can produce a range of Unicode characters in Word with keypad numbers that won’t work in other applications like Notepad or this browser. The subset called Latin Extended-A.
Maybe not what OP is looking for, but due to the inconsistent keypad behavior I find it easier to go into the Character Map application, find the character, and copy and paste it wherever I need it.
Copying and pasting from a character map application, or manually typing characters by Unicode codepoint, is OK as a one-off solution, but if there’s any possibility you’ll need to type the same characters on a regular basis, you’d be better off switching to a keyboard layout that contains those characters, possibly accessible only via dead-key or AltGr combinations. If no existing layout on your OS contains all the characters you need, you can always create your own layout, those some OSes don’t provide any standard way of doing this. (I regularly need to type in five different Latin-script languages, sometimes in the same document, and so created my own keyboard layout with all the necessary glyphs and dead-key diacritics.)
UPDATE: and now I found that even using Alt-alpha combinations that are reserved for my browser (Chrome) menu items, I can still just use Esc to exit and the Unicode character string entry continues uninterrupted.
For example, if I want to enter the Unicode character with the hex code 215E:
I hold down ALT
push the + sign on the 10-key pad (that’s important, the other + doesn’t work)
What works for me is to type the four digit code then Alt-x. This doesn’t require using the numeric keypad. It works in Word and some other places but not here. Some programs don’t support all those characters. Here it only seems you can get the higher ASCII characters by holding the alt key and typing a three digit code on the numeric key pad (be sure Num Lock is on).