eSIM for iPhone 6S

I have an old iPhone 6s I want to use on trip to Cuba (I don’t want to bring my current one for risk of losing it). It has no physical SIM in it. Can I download Airalo eSIM on it and use it in Cuba?

if so, before I pay and download the app onto the phone, will I be able to activate directly through the app?

On my current iPhone in settings - general - cellular, there is option to “add eSIM” but on my iPhone 6, cellular says no SIM and I can not toggle to anything else.