I'm currently on macOS and I will be moving to Windows soon, and one of the ways to quickly excess extended characters is by pressing and holding a key, e.g. 'a' and the following popover appears (see image below). Is there a native way to do this this intuitively on Windows? If not, is there any third party software capable of providing a similar functionality? Thanks in advance!
The Keyxpat tool allows to access any set of characters you define when typing and holding specific keys. For example, hold E and you will be able to choose between é, è, ê, ë, either visually or thanks to a fast metronome telling you when to release the key. That way, there is no weird shortcuts to remember and it does not make your fingers move elsewhere than the logical key where to find an accent or a special character. Of course this is highly configurable.
Feel free to ask questions, I'm the author.
Update: I realized that, beyond being able to access accents, you also wanted a visual way to access them. Note that the current version in development has such a visual aid. You could contact me to try it in early access. In my vision, the visual aid is fine to start using the tool. Then, when you are used to the metronome way of selecting the desired character, you may want to switch to the non visual way of using Keyxpat.
I don't know of a direct replacement for the Apple structure, but you can achieve something vaguely similar if you set your keyboard layout to one of the English International layouts.
International layouts use a dead-key system, rather than a pop-up. The Mac used to use a similar system by default, before the popup was transitioned from iOS to macOS. I don't know whether you're familiar with this, but the structure is to hold Opt then an 'accent' key, then type the letter you want the accent over - so Opt e followed by a gives á Opt u followed by o gives ö etc. The orange keys become dead keys with Opt held...
The Windows International layouts give a similar kind of replacement - except you don't press Opt [Alt], you just hit the dead key followed by your letter [or by spacebar to use just the 'dead' character.]
I can't add a picture for the Windows keymap as there's no equivalent to show which are dead keys.
Control Panel > Region & Language > Keyboards & Language > Change Keyboards...
Here I have first set my Language to the correct one for my physical keyboard & Location (English UK), then underneath I have a switch between US International (with the dead-keys) & 'standard' UK Extended (without dead-keys).
The switch between US & UK is because it also moves the locations of @ and " which clash with my usual Mac keyboard layout which I'm most accustomed to.
