Reference
How to type the new letters
There is no dedicated Uzbek layout for Ş, Ç, Ö and Ğ yet. The most reliable route is to add the Turkish (Q) keyboard — all four letters are on it.
Ready-made letters
Tap a letter to copy it.
Windows
Settings → Time & language → Language & region: add “Türkçe” and keep “Turkish Q” as its keyboard. Switch with the language-bar button or Windows+Space. On the Turkish Q layout, ğ, ş, ö and ç each sit on their own key.
Windows: Alt codes
Ç, ç, Ö and ö can also be typed by holding Alt and entering a code on the numeric keypad: Alt+0199, Alt+0231, Alt+0214, Alt+0246. Ş and Ğ are absent from the standard Windows code page, so no Alt code works for them — use the Turkish layout or the ready-made letters above.
macOS
System Settings → Keyboard → Text Input → Edit: add “Türkçe — QWERTY” as an input source. Switch from the menu-bar flag or with Ctrl+Space. If you only need ö and ç, you can skip the Turkish layout: Option+U then o gives ö, and Option+C gives ç.
Android (Gboard)
Gboard settings → Languages → Add keyboard → “Türkçe”. After that, long-pressing a key reveals the new characters: s → ş, g → ğ, o → ö, c → ç. On many devices long-press works even without switching layout.
iPhone and iPad
Settings → General → Keyboard → Keyboards → Add New Keyboard → “Türkçe”. Then press and hold a letter and pick ş, ğ, ö or ç from the options that appear.
Would rather not set up a keyboard?
Write in the current alphabet and run the text through the converter — all four letters are replaced for you, and the formatting survives.