Hola John

In Peninsular Spanish we use preposition "por" to say "in the morning", "in the afternoon", and "in the evening". In some parts of Northern Spain preposition "a" is sometimes used too, but this is not the general use. 

You may have heard "en" but that would be in some parts of Latin America, not in Spain.

Kwiziq is focused on Peninsular Spanish at the moment, although we plan to have a Latin American version too at some point in the future.

Un saludo

Inma

Hola Johan

I imagine you are referring to this question "Normalmente ceno con la familia por la noche."

We could say "...con mi familia", but when it is obvious that you are referring to your own family, in Spanish we don't need the possessive "mi", we use the article "the" instead. But both would be correct, though.

Hope this helps.

Inma