What operating system are you using?

I use Apple. MacBook air

In the Mac OS control panel Keyboard you can choose a keyboard layout that makes it easier to enter text in a specific language.

For e. g. text in german you might prefer a german keyboard layout.

Also, you can in Mac OS enable the Keyboard menu, with easy access to keyboard layout switching, and easy access to a pane where you can choose font characters and emojis.

The dialog box Symbol Selection in Finale lets you choose a character in the selected font.

I thought I'd jump in on this before there comes a barrage of [understandable] April Fool's Day responses from forum members.

Sorry Katy, but you're not giving us anywhere near enough information. What exactly are you trying to write? Music? Text? Is your problem that you have a Cyrillic keyboard and you're trying to write text in a Western language?