Adding to this - In addition to the unicode character method, I’ve now set up PT as a second language on the Win10 machine.
Settings -> Time & Language -> Language -> Preferred Languages
Add Portuguese (Portugal)
Then in the Settings search bar, enter ‘Advanced’ and select Advanced Keyboard Settings. From there, select Language Bar Options, and then on the Language Bar tab, select Docked in the taskbar.
This will put a ‘POR’ option in addition to the ENG (for me) option in the taskbar. Now I can easily switch between keyboard layouts; either with o rato, or Left Alt + Shift (see the ‘Advanced Key Settings’ in the same advanced window).
To see the virtual keyboard, type: winkey+ctrl+o - this brings up the on-screen keyboard in the current lang setting.
HTH…
oSteve