Typing on smartphone keyboards can often be a frustrating experience, especially when typing unusual symbols or any accented letters not present in the basic English alphabet. As it turns out, Windows 10 Mobile's software input panel (the keyboard that pops up when typing) for English features a huge variety of hidden keys that can help with this.
To actuate them, simply press and hold certain keys, and in less than half a second, several additional options related to that particular key will pop out. For example, holding on the letter "A" will pop out almost every variety of that particular key.
Some keys, such as L or Backspace, either have no derivatives or expose an essential function that must allow for the possibility of holding.
Hidden in the top row of alphabet keys are also the numbers "0" through "9".
Particularly cumbersome is typing certain symbols such as + or =, which require jumping through two pages of software keys. To access these hidden keys, tap on the "." button. This will expose some of those symbols.
It's important to note that SIPs in Windows 10 Mobile can change depending on the occasion. For instance, when typing a URL or search in Edge's address bar, you'll get a SIP tailored specifically to typing web URLs, which includes the convenient ".com" button.
When typing a message, you'll get a different set of keys, with no ".com" button. As such, often range of hidden keys changes along with their corresponding SIP variations.
I highly recommend taking a moment to experiment with exposing and learning all the hidden keys, as knowing them could save you a lot of headache and frustration in the future should a situation arise that requires using them.