What effect gives an electronic tone to the voice

Ye is short for Kenya (West) and when you have to make up your own nickname, that's just sad.

But to the OP; To get a vocoder sound, you need an actual vocoder plugin and they usually won't work in FCP. Most vocoders, including TAL, require doing a side-chain to a MIDI track. It won't work in FCP. You'll need to take your audio track to Logic (or some other DAW) and use an actual vocoder plugin.

Final Cut *should* have an audio effect called Robot... you should be able to get what you want from it.

HTH

You might also find the TAL Vocoder useful:

https://tal-software.com/products/tal-vocoder

I believe it's free... (still). Claims to support Intel and M1..M4 processors.

kinda like Ye uses?

Who is "Ye"? what? Please let me know the link.