In USSR taxes were auto-deducted from salary and were lower for people with children, for example.

im pretty sure they just taken from the salary

I found this, but the writing is a little odd, so I’m not vouching for veracity:

https://modacode.ru/en/nalogovaya-sistema-sssr-struktura-nalogooblozheniya-v-gody-sssr/

I couldn’t find anything that looked remotely credible for Cuba, I will look again later if I have time and remember, I have to start my day.