If a person missed some days of fasting in ramadan due to menstruating or travel, and a year passes and a new ramadan passes too.
Q1. What does the person have to do then? Fast the missed days only? Or fast and give kaffara? Or only kaffara?
Q2. And if kafarra has to be paid how many would it be?
Q3. And what if a person can’t afford it?

1- Fast the missed days+ paying 0.75 kg of food (Rice, flour, dates) per day to a needy momen.

Example: If the missed days are 6, then you need to pay 0.75 x 6= 4.5 kg

2- Already answered.

3- You do not need to pay it at once. You can pay it gradually.